Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra … de abstracts.pdf144 Cavaleiro A. 16, 39, 79, 96, 102 Chigiatto P. 81 Coelho B. 24 Colera I. 114 Colligon J.S. 15 Contreras-Puente

149

Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra G. 129 Yubero F. 20, 23 Yurasova V.E. 15 Zelaya-Angel O. 17, 127, 128 Zykova E.Yu. 15

148

Rusu G.I. 131 Rusu M. 126, 131 Ryzhov Yu.A. 15 Sacedón J.L. 25, 72 Sánchez O. 100, 103 Sánchez-López J.C. 101 Sanguino P. 116 Schwarz R. 116 Shakarban I.I. 15 Silva R.F. 9, 99-140 Simao R.A. 99 Smail H. 46 Solis J. 78 Soriano L. 10 Stupnik A. 88 Tabarés F.L. 30, 33 Tafalla D. 33 Tavares C.J. 21, 117 Teba, D. 61 Teixeira M.R. 90 Teixeira V. 21, 117 Teodoro O.M.N.D. 48, 70, 89, 91, 116, 120 Tesar J. 69 Tessema G. 122 Tikhomirov A.V. 31 Tilford Ch. R. 6 Torres-Kauffman J. 128 Trigo J.F. 10, 61 Valencia-Alvarado R. 124 Vanhulsel A. 94 Vaz F. 75, 98 Vázquez E. 121 Vázquez L. 37 Verheyde B. 94 Verhoeven J. 56 Vicar M. 69 Vidal-Larramendi J. 127 Vieira P. 93 Vigil-Galán O. 127 Vila M. 24,138 Vilajuana T. 64 Villuendas F. 60 Völklein F. 106 Wemans A. 42,45,48 Wilhelm M. 116

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Oliveira F. J. 140 Orts M.J. 76 Otal P. 71 Ouchabane M. 125 Paiva A.C.S. 95 Palacín S. 10 Palomino-Merino R. 128 Pardo A. 113 Parreira N.M.G. 16, 102 Patscheider J. 14 Pearce R.J.H. 82 Peksa L. 69 Peña-Eguiluz R. 124 Pereira P.J.S. 90 Pérez-Martín A.M.C. 22 Piechowiak M. 44 Pinto R.M. 92 Polcar T. 16, 96 Portillo-Moreno O. 17, 128 Powell S. 58 Prazak D. 69 Preda I. 10 Prepelita P. 131 Prieto C. 26, 138 Raboso D. 130 Ramos A.R. 21 Ramos-Barrado J.R. 47 Rayon E. 11 Rebouta L. 98 Reid R.J. 50 Reis E.M.C.C. 89 Repa P. 69 Ribera J. 77 Rico M. 104 Rico V. 23 Rico J. 20 Rios P. 113 Rodríguez R.J. 36, 38, 104, 112 Rodríguez-Cañas E. 25 Román E. 94, 109, 130 Romero J. 13 Rueda F. 121 Ruiz A. 130 Ruiz S. 53 Rusu G.G. 126

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Leinen D. 47 Leisch M. 88 Lévy L. 113 López-Callejas R. 124 López-Cartes C. 101 López-Ibáñez R. 47 Lousa A. 13, 41 Lozada-Morales R. 17, 128 Lozano P. 130 Lucas F. 76 Maneira M.J.P. 42, 45, 48, 90 Marco J.M. 59 Mardare D. 119 Mari D. 67 Marín M. 100 Marques H.P. 48, 70, 91 Marques S.M. 21, 117 Martín F. 47 Martínez L. 94 Martínez R. 36, 38, 104 Martínez-Martínez D. 101 Matilla C. 32, 53 Matveeva E. 11, 63 Medina N. 53 Meier A. 106 Mejia J.P. 41 Mendez J. 94 Mercado-Cabrera A. 124 Miralles LL. 107 Mohammedi L. 137 Moina C. 129 Montero I. 112, 113, 130 Mosunov A.S. 15 Moutinho A.M.C. 70, 91, 120 Moya J.S. 72 Muñoz-Castro A.E. 124 Narayanan K.L. 17 Neto M.A. 9 Nevshupa, R. 109 Nunes Y. 42, 45, 48 Nunzi J.M. 118 Ochando I.M. 26, 138 Orgaz F. 79 Oliva A.I. 25 Oliveira F. 24

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Gabouze N. 125 Galán L. 112, 113, 130 García G. 36 García J.A. 36, 38, 79, 104 García M. 130 García-López F.J. 26 García-Luis A. 12, 129, 136 García-Rocha M. 128 Garg D. 20 Gheriani R. 133, 137 Gikal B.N. 31 Girtan M. 118, 126 Godoy-Cabrera O.G. 124 Gomes J.R. 99 Gomes M.J.M. 44 Gómez-Aleixandre C. 37 González D. 12, 129, 136 González R. 114 González-Elipe A.R. 20, 23, 43, 62 Gordo P.R. 42, 45 Gracia F. 62 Gronych T. 69 Guerra M. 95 Gulbekian G.G. 31 Gutierrez A. 10 Gutiérrez M.T. 27 Hadjar Y. 135-139 Halimi R. 133, 134, 135, 137-139 Harkati C. 134 Herrasti P. 121 Hidalgo J.M. 52, 68 Högberg H. 86 Huttel Y. 94 Jacobs R. 94 Jensen H.S. 108 Jiménez-Rioboó R.J. 26 Jiménez-Rodríguez J.J. 22 Jiménez-Sáez J.C. 22 Jousten K. 29 Khalfallah F, 139 Khodorov A. 44 Kreissing U. 98 Kunst M. 116 Lara A. 61 Legras J-C. 71

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Cavaleiro A. 16, 39, 79, 96, 102 Chigiatto P. 81 Coelho B. 24 Colera I. 114 Colligon J.S. 15 Contreras-Puente G. 127 Corengia P. 136, 129 Costa F.M. 9 Costa M.L. 89, 92, 93 Cotrino J. 20, 43 Cristo P.M.S. 93 Dabos-Seignon S. 118 Daniel B. 58 Day Ch. 108 de la Piedad-Beneitez A. 124 de la Rosa-Vázquez J. 124 de las Heras E. 129 de Segovia J.L. 52, 68, 109, 112, 113, 114 Devia A. 41 Dias A.A. 89,92, 93 Díaz B. 100 Díaz M. 72 Díaz R. 121 Duarte A. 24 Dumitru L. 119 Van Eesbeek M. 113 Elovikov S.S. 15 Escobar Galindo R. 11, 26 Escrivao M.L. 90 Espinós J.P. 20, 23 Esteve J. 41 Evaristo M. 96 Falcony C. 103 Fazio G. 83 Ferreira Q. 48 Fernandes A.J. 21, 117 Fernandes A.J.S. 9, 24-140 Fernández A. 101 Ferrerira J.A. 30, 33 Ferreira R. 19 Fonseca A.P. 70 Freitas P.P. 19 Freitas S. 19 Frutos F. 23 Fuentes G.G. 38, 112

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AUTHOR’S INDEX Aouabdia Y. 46 Ababou A. 125 Abb el Lefdil M. 121 Abdel Hamid B. 46 Achete C.A. 99 Acuña R. 61 Afonso C.N. 65 Agote I. 136 Aguilar-Hernández J. 127 Aissani L. 134 Ait-Hamouda K. 125 Al-Dmour E. 107 Albella J.M. 11, 37, 79,103 Alberdi A. 76, 100 Almeida F. A. 140 Álvarez L. 94 Alves E. 21, 98 Amaral M. S. 140 Andrés M. 27 Araiza J.J. 103 Arias-Carbajal A. 127 Auger M.A. 103 Aznárez J.A. 25 Baban C. 131 Barocio S.R. 124 Barradas N.P. 98 Barranco A. 43, 62 Belda A. 76 Bellido-González V. 58 Bergoglio M. 67 Boineau F. 71 Borrás A. 43, 62 Brizuela M. 12, 129, 136 Buijnsters J.G. 37 Cáceres D. 26, 114 Calcatelli A. 67 Camargao S.S. 99 Camero M. 37 Canário A.R. 91, 120 Carda J. 77 Carneiro J.O. 21, 117 Carrapichano J.M. 99 Carvalho P. 75

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AUTHORS’S INDEX

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JUNE 28 WEDNESDAY AFTERNOON

JS2-WeA-P.8 NANO TO MICROMETRIC HFCVD DIAMOND ADHESION STRENGTH TO Si3N4. F.A. Almeida, M.S. Amaral, F.J. Oliveira, R.F. Silva. Dept. of Ceramics and Glass Engi-neering, CICECO, Univ. of Aveiro, 3810-193 Aveiro, Portugal. A.J.S. Fernandes. Dept. of Physics, Univ. of Aveiro, 3810-193 Aveiro, Portugal CVD diamond coated materials possess unique properties (hardness, thermal conductivity, chemical inertness) that demand their selection as components of tribosystems working under mechanicaland/or chemical severe conditions. Examples of such applications are cutting tools for highly abrasive materials and mechanical seals for pumping of corrosive liquids. Furthermore, an increasing interest-ing field of application is biomedicine, namely cirurgical tools and coatings for articular implants, where diamond’s biocompatibility is an essential issue. However, the high surface roughness of con-ventional microcrystalline CVD diamond is a major problem when considering such purposes, as thesliding contact of diamond asperities may increase stress and temperature levels, leading to an increas-ing wear rate. To overcome this drawback, today’s goal is the development of diamond crystals with very small grains of nanometric size by adequate CVD parameters, avoiding the typical columnargrowth of microcrystalline diamond structures. When considering tribological and mechanical applica-tions, adhesion of the film to the substrate determines the success of the component in service. In thisstudy, distinct diamond coatings on silicon nitride ceramic substrates with different crystallite sizes were investigated: i) nanocrystalline diamond (~25 nm); ii) submicrometric diamond (~ 40 nm); and iii) conventional micrometric size (~10 μm). The coatings, with thickness of about 40 μm, were grownby hot filament CVD technique. The effect of these diamond structures on adhesion strength to the ce-ramic substrate will be evaluated by Brale tip indentation and correlated with their Raman signature.

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JS2-WeA-P.7 STUDY OF SOME PROPERTIES OF HARD TUNGSTEN CARBIDE COATINGS. F. Khalfallah, Y. Hadjar, R. Halimi. Laboratoire des Couches Minces et Interfaces, Département de Physique, Faculté des Sciences, Université Mentouri, 25000 Constantine, Algérie.

In this work, we have studied the properties of hard coatings of tungsten carbides. The samples are thin layers of Tungsten deposited at 500°C on two types of steel (containing 1 and 0,7% wt. carbon) substrates. The samples were then heat treated in vacuum, at various temperatures (500-1000°C) and during different times. The formation of tungsten carbides, the evolution of the microstructure and the morphology of the sur-face of samples were followed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The measurements of micro-hardness were carried out by Vickers tests. Thermal annealing produces reactions and some other structural changes in the tungsten layers whichdepend on the carbon content in substrate. It is established that the formation of tungsten carbides occurs above annealing at 800°C. The reaction is more rapid on substrate containing 1%C. The mono-carbide WC forms after annealing at 1000°C. The hardness of coatings increases continuously from 400 to 1200 Kg/mm² as the temperature of an-nealing increases from 500 to 900°C. The samples rich on carbon show higher hardness. Key words: hard coatings, tungsten, carbides, thin films. Presenting author: F. KHALFALLAH Contacts and email: Tel/Fax: 213 31 61 47 11; [email protected] Presentation type: Poster

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JS2-WeA-P.6 OPTICAL AND STRUCTURAL STUDY OF EB-PVD ZrO2 THIN FILMS.I. M. Ochando, M. Vila and C. Prieto. Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas. Cantoblanco, 28049 – MADRID, Spain.

Zirconium oxide is a widely used material because of its heat resistance, low thermal conductivity,high refractive index and high transparency in the visible and near infrared region, very high chemical inertness and high laser damage threshold. Due to these properties, its applications can be found in very different aspects of technology. For instance, zirconia has been applied as thermal barrier coating(1), optical filters, laser mirrors(2), buffer layer for high TC superconductor on Si (3), high temperature oxygen separation (4), oxygen sensors(5), and solid oxide fuel cells(6).

Films of zirconia can be prepared by different techniques. Typically, thin films prepared by sputtering are used for gate dielectric in microelectronics applications and zirconia films prepared by electron beam physical vapour deposition (EB-PVD) are candidates for advanced thermal barrier coatings (TBC) for the new generation of land-based gas turbines as well as for optical applications. In the in-terest host materials with a high luminescent efficiency and superior stabilization, tetragonal ZrO2 is an attractive material due to the refractive index, electrical, chemical and mechanical characteristics.

ZrO2 thin films prepared on Si(100) substrates by electron beam physical vapour deposition (EB-PVD) are investigated by X-ray diffraction and optical absorption spectroscopy. Results show tetrago-nal stabilized phases of zirconium oxide independently of the yttria addition in the starting material. Inthis work, it is reported the variation of the crystallite size as a function of the deposition rate, showing that crystallites are in the nanometric range and that a remarkable crystallite size increase is observable for thin films prepared at low deposition rates. In addition, it is presented the optical absorption spectroscopy characterization in order to determine the refractive index; the obtained values does not depend on the deposition rate being in agreementwith the bulk ones. It is shown EB-PVD prepared samples have good performance for optical and pro-tective coatings. S.M. Meier, D.K. Gupta, J Eng. Gas Turbines Power Trans. ASME 116 (1994) 250. 2 W.H. Lowdermilk, D. Milam, F. Rainer, Thin Solid Films 73 (1980) 155. 3 D.K. Fork, D.B. Fenner, G.A.N. Connell, J.M. Phillips, T.H. Geballe, Appl. Phys. Lett. 57 (1990) 1137. 4 J. Han, Y.Zeng, G. Xomeritakis, Y.S. Lin, Solid State Ionics 98 (1997) 63. 5 M. Sayer , K.Sreenivas, Science 247 (1990) 1056. 6 N.Q. Minh, J. Am. Ceram. Soc. 76 (1993) 563.

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JS2-WeA-P.5 ELABORATION AND CHARACTERIZATION OF THIN TITANIUM COATINGS ON HIGH CARBON STEEL SUBSTRATES. L. Mohammedi. Laboratory of Mate-rials Physic. University of Ouargla – 30 000 – Algeria. R. Gheriani. Laboratory of Materials Physic. University of Ouargla – 30 000 – Algeria. R. Halimi. Laboratoire Couches Minces et Interfaces, Cam-pus Chaâb Erssas, Université Mentouri de Constantine - 25 000 Constantine – Algérie.

In this work we have elaborated, by cathodic sputtering, thin titanium coatings on steel substrates con-taining ≈ 2% Wt of carbon. The so prepared samples are submitted to various thermal anneals in vac-uum between 400°C and 1000°C, and then characterized structurally and mechanically by X-ray dif-fraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and hard-ness tests. The analysis of samples showed the formation and the growth of titanium carbide above400°C. It is established that carbon, iron and titanium atoms interdiffuse intensively, and form a diffu-sion zone which is, roughly, homogeneous and essentially constituted from titanium carbide. This new layer presents a good performances (for example, at 900°C, the value of microhardness is Hv = 3200 kg mm-2, which is larger than that of bulk TiC Hv = 3000 kg mm-2). Key words: thin films, hard coatings, carbide, diffusion, titanium

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ETCHC-WeA-P.4 DEPOSITION OF Ti-B-Al-N COATINGS BY MAGNETRON SPUT-TERING OF COMPOSITE SHS TARGETS. A. García-Luis*, M. Brizuela, P. Corengia, D. Gon-zález, I. Agote. INASMET-Tecnalia, Paseo de Mikeletegi 2, 20009 San Sebastián, Spain The synthesis of complex multicomponent coatings by magnetron sputtering usually involves the use of several single-material targets, multi-material targets or composite targets. There are several meth-ods of producing composite targets, for example, hot pressing, hot extrusion, hot isostatic pressing or plasma spraying of the component materials of the target. However, each of these methods has some limitations regarding purity, porosity, uniformity of the microstructure or manufacturing costs. Self-Propagating High-temperature Synthesis (SHS) is an energy-efficient alternative method which uses exothermic reactions to synthesize compact and pure inorganic materials, including intermetallics, ce-ramics and ceramic composites. In this work, Ti/TiB2 (5 % Al) composite targets produced by the SHS technique has been used to de-posit PVD coatings based in Ti-B-Al-N compositions. The process optimization has included the study of the experimental parameters (cathode power, gas flows and heating on the chamber) on thecoating properties. Mechanical properties have been evaluated by dynamic ultramicroindentation techniques and scratch testing, while tribological tests have been carried out against ball bearing steel by the pin-on-disk method. Ultramicrohardness values up to 36 GPa, together with a very good elastic behaviour (elastic work 92%) have been obtained for some selected Ti-B-Al-N coatings. The adhesion of these coatings to steel substrates has been satisfactory, with values of critical load in the scratch test higher than 55 N. Fi-nally, the wear tests confirm the good tribological properties of these coatings, giving no measurable wear of the coated disk after the pin-on-disk test.

* Corresponding author: Tel: +34 943 003700; fax: +34 943 003800, e-mail: [email protected]

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JS2-WeA-P3 CARBIDES FORMATION IN TANTALUM THIN LAYERS DEPOS-ITED ON STEEL SUBSTRATES. Y. Hadjar. Institut de Tronc Commun Sciences Exactes etTechnologie, Université de Batna, Algérie, R. Halimi, Laboratoire Couches Minces et Interfaces,Université Mentouri, 25000 Constantine, Algérie. In the present work we are intending to elaborate and to study thin film coating of tantalum carbides on steel substrates. The procedure used in order to prepare the samples consist on depositing, by electron gun evaporation, a thin film (4µm thickness) of tantalum on steel substrates containing 1 %wt. of carbon, then, annealing the system (substrate/coating) in vacuum at a temperature at which the carbon of the substrate may diffuse into the Ta metallic film. This fact leads to the formation of tantalum carbides. The effects of the annealing on the kinetic of tantalum carbides formation and morphology have been investigated using X- ray diffraction (XRD), secondary ion mass spectros-copy (SIMS) and scanning electron microscopy (SEM). The mechanical characterization was per-formed by measuring microhardness and adhesion. It is found that at annealing up to 800°C the compounds Ta2C and TaC are formed. During the subsequent heat treatment from 900°C to 1100°C the final TaC phase grows at the expense of the Ta2C phase. Moreover, the microhardness and adhe-sion of the films increase significantly with increasing annealing temperature. At a given tempera-ture, the microhardness increases, with the rise of the annealing time, to reach a maximum and then decreases. The final coating layer has a golden color and presents a columnar structure. The forma-tion mechanisms are discussed. Key words: hard coatings, tantalum carbides, thin films, diffusion. Presenting author: R. HALIMI E-mail: [email protected] Presentation type: Poster

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JS2-WeA-P.2 SYNTHESIS AND CHARACTERIZATION OF THIN HARD COAT-INGS OF CHROMIUM CARBIDES. L. Aissani. Département de Physique, Centre universitaire de Khenchela, Algérie. C. Harkati, and R. Halimi. Laboratoire Couches Minces et Interfaces, Dépar-tement de Physique, Faculté des Sciences, Université Mentouri, 25000 Constantine, Algérie.

Hard chromium carbide coatings were elaborated by depositing a chromium layer ( 3μm or 1 μm thickness ), using the physical vapour deposition technique of magnetron sputtering, on carbon steel substrates and, subsequently, annealing the system in vacuum at temperatures from 200°C to 1200°C. Structural characterization was assessed using scanning electron microscopy and X-ray dif-fraction. Some mechanical properties such as micro and nano-hardness and residual stresses were studied. It was found that the binary carbides Cr7C3, and Cr23C6 appear at 700°C and 900°C respec-tively. The Cr7C3 compound transforms then at 1000°C into ternary carbide (Cr,Fe)7C3. It was showed that the micro and nano-hardness increase with the rising of annealing temperature until reaching a maximum value and then decreases. The increase of the hardness is associated to the chromium carbides formation, which are harder. However, its decrease is due to the iron atoms dif-fusion into the coating layer. Thicker Chromium coatings present a better adhesive properties. It is, also, observed that the compressive residual stresses in coating (σϕ = -734 MPa at 900°C) become tensile at 1000°C (σϕ = 127 MPa). Keywords: Chromium, coating, carbides, thin films

Presenting author: L. AISSANI E-mail: [email protected] Presentation type: Poster

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JS2-WeA-P.1 IMPROVEMENT OF MECHANICAL PROPERTIES OF STEEL SUBSTRATES SURFACE BY DEPOSITION OF THIN TITANIUM FILMS OBTAINED BY MAGNETRON SPUTTERING METHOD. R. Gheriani. Physical laboratory of Materials, Uni-versity of Ouargla , 30.000- Algeria. R. Halimi. Unity of research, Materials and applications, Uni-versity of Constantine, 25.000 – Algeria. Titanium carbides are well known materials with great scientific and technological interest. The ap-plications of these materials take advantage of the fact that they are very hard, refractory and that they have metallic properties. In this work, We have studied the influence of the heat treatment temperatures ( 400-1000°C) on the interaction between the titanium thin films and steel substrates. Steel substrates, 100C6 type (AF-NOR norms), containing approximately 1 wt % of carbon, were coated at 200°C with titanium thin films by magnetron sputtering. The samples were characterized by X ray diffraction (XRD), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). Vikers micro-hardness measurements carried out on the an-nealed samples showed that the micro-hardness increases with annealing temperature, reaches a maximum (3500 kg/mm2), then decreases progressively. The growth of micro-hardness is due to the diffusion of the carbon, and to the formation of titanium carbide. However, the decrease of micro-hardness is associated to the diffusion of iron and the formation of iron oxide (Fe2O3). At higher temperatures, we note the formation of titanium oxide (TiO2).

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JS1-WeA-P.8 ON THE INFLUENCE OF TE EXCESS ON THE OPTICAL PROP-ERTIES OF VACUUM EVAPORATED ZNTE THIN FILMS. P. Prepeliţă, M.Rusu, C.Baban, G.I.Rusu. Faculty of Physics “Al. I. Cuza” University, B-dul Carol I, No.11, Iasi, Romania. (e-mail: [email protected]) ZnTe thin films are intensively studied due to their interesting properties such as high transmission coefficient, large energy bandgap, low electrical resistivity, etc. An important factor that influences the properties of these films is the deviation from their stoichiometric composition. In present paper, the influence of tellurium excess on the optical properties of evaporated ZnTe thin films is investi-gated. The studied films (d = 0.700 µm - 1.300 µm) were deposited onto unheated glass substrates by evaporation under vacuum of ZnTe powder at source temperature ranged between 900 K and 1200 K. The structural analysis of the films was performed by XRD and AFM techniques. The optical pa-rameters (refractive index and absorption coefficient) both for as deposited and heat treated samples were determined from transmission spectra in the spectral range 340 nm - 1400 nm. It was found that the studied films present a polycrystalline zinc blende structure with preferential orientation of (111) planes parallel to the substrate. An excess of tellurium atoms which aggregate in crystallite form during film annealing was observed. This Te excess determines a significant increase of the absorption coefficient near the fundamental absorption edge and of refractive index in the in-frared domain. Depending on Te content, the optical bandgap energy, Eg, calculated from the absorp-tion spectra, ranged between 1.9 eV and 2.4 eV. The results are discussed in correlation with film structure and the impurity levels introduced by the Te excess.

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JS1-WeA-P.7 UHV REACTIVE EVAPORATION GROWTH OF TITANIUM NI-TRIDE THIN FILMS, LOOKING FOR MULTIPACTOR EFFECT SUPPRESSION IN SPACE APPLICATIONS. Ana Ruiz and Elisa Román. Instituto de Ciencia de Materiales de Ma-drid. Consejo Superior de Investigaciones Científicas. Cantoblanco. E-28049-Madrid. Spain Pilar Lozano*, Mariano García and Luis Galán. Departamento de Física Aplicada. Universidad Autónoma de Madrid.Cantoblanco. E-28049 Madrid. Spain. Isabel Montero. Instituto de Ciencia de Materiales de Madrid. Consejo Superior de Investigaciones Científicas. Cantoblanco. E-28049-Madrid. Spain. David Raboso. ESA/ESTEC. Keplerlaan, 1. 2200 AG Noordwijk. The Netherlands.

A low secondary electron emission yield which remains stable after exposure to ambient, as well as a good electrical conductivity, have proved to be basic criteria for selecting a reliable coating in RF components for space applications, in order to reduce the multipactor effect. Although titanium ni-tride is among the most appropriate materials, its actual performance is very much dependent on the deposition conditions. Standard deposition techniques used for TiN thin films or coatings often pro-duce layers that are far from optimal, specially concerning secondary emission yield and its stability when exposed to air. In this work, an ultra-high vacuum reactive evaporation procedure has been tested and optimized for the growth of TiN thin films, throwing very good results both in composition of the TiN layers and SEY values and performance. Sublimation of Ti filaments is carried out in a ultra-high vacuum chamber in which a controlled leak of high purity N2 is placed close to the substrate surface, thus maintaining the overall pressure in the high vacuum range and preventing nitridation of the Ti fila-ments. Detailed description of the growth procedure, substrate preparation and deposition protocol will be described with special emphasis on the relevant growth parameters and practical hints and how to achieve them. We present a study of the samples grown, such as stoichiometry and composi-tion obtained by means of XPS and AES, and secondary electron emission measurements versus time in the scale of several months. The results obtained show that the deposition technique throws the best results towards the multipactor effect suppression. *present address: Instituto Universitario de Investigación en Nanociencia de Aragón. Universidad de Zaragoza. Edificio Interfacultativo II. c/ Pedro Cerbuna,12.E-50009 Zaragoza (Spain)

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JS1-WeA-P.6 DC-PULSED PLASMA NITRIDING (DCPPN) OF STANLESS STEEL: MICROSTRUCTURE, CORROSION A WEAR BEHAVIOUR. P. Corengia1, E. De Las Heras2, M. Brizuela1, D. González1, A. García-Luis1, G. Ybarra2, C. Moina2. 1Fundación INASMET-Tecnalia, Paseo de Mikeletegi 2, 20009 San Sebastián, Spain. 2Instituto Nacional de Tecnología In-dustrial, Av. Gral. Paz 5445, C.C. 157, (B1650 WAB) San Martín, Argentina. Stainless steels are usually employed as engineering materials due to high corrosion resistance. However, low wear resistance and poor tribological behaviour limit their use in some industrial ap-plications. Therefore, there is an increasing interest in improving surface properties through plasma assisted treatments, notably ion nitriding. Although stainless steels can be nitrided with the conse-quential increase in surface hardness, which improves their tribological performance, this is accom-panied by a loss of corrosion resistance of the nitrided case. Nitriding of stainless steels leads to a depletion of chromium content in the matrix, thus reducing the corrosion resistance of the nitrided layer. In the present work, industrial-scale DC-pulsed plasma nitriding for 20 h at 673K was used to im-prove the surface properties of both martensitic (AISI 410) and austenitic (AISI 316L) stainless steels. The effect of nitriding on structural and mechanical properties of the nitrided layer was inves-tigated by optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and microhardness. The tribological behaviour was studied and compared to the behaviour of the same steel in as-received condition. The wear resistance was investigated using an Amsler-disc-machine, employing a dry combined contact of rolling–sliding with three different applied loads. The wear mechanisms involved during the test of unnitrided and plasma nitrided steels were investigated by microscopic observation of the surfaces, the corresponding cross-sections and the produced wear debris. In addi-tion microhardness profiles were done in order to evaluate the work hardening effect during the wear process. Electrochemical experiments in 3% NaCl solution were carried out to characterize the cor-rosion behaviour of unnitrided and nitrided stainless steels. Analysis and discussion of the tribological results show that plasma nitriding improves the wear re-sistance of the surface on stainless steels and the main wear mechanism appears to be delamination. Consequences on the load bearing capacity are discussed. The modified layers of the nitrided AISI 316L steel were composed of “expanded austenite”, while the nitrided AISI 410 samples were characterized by the presence of “expanded ferrite”, CrN and Fe4N. The DCPPN samples of both AISI 316L and AISI 410 revealed a surface hardness above 1000 HV and a sharp interface between the case (nitrided layer) and the core (matrix). Results of electrochemical measurements of unnitrided and DCPPN specimens were analysed and related to the microstructural characteristics of the nitrided case. Corresponding author: Tel: +34 943 003700; fax: +34 943 003800, e-mail: [email protected]

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JS1-WeA-P.5 PHOTOLUMINESCENCE OF RHODAMINE 6G DOPED AMOR-PHOUS TIO2 THIN FILMS GROWN BY SOL-GEL. R. Palomino-Merino1, J. Torres-Kauffman1, R. Lozada-Morales1, and O. Portillo-Moreno2, Benemérita Universidad. Autónoma de Puebla. 1Posgrado en Optoelectrónica, Facultad de Ciencias Físico-Matemáticas. 2Facultad de Cien-cias Químicas. México. M. García-Rocha, and O. Zelaya-Angel. Department of Physics. Centro de Investigacion y de Estudios Avanzados del IPN. P.O. Box 14-740, Mexico 07360 D.F. Rhodamine 6G doped amorphous titania thin films were prepared by the sol-gel technique. The films were grown at room temperature and supported on silica-glass substrates which were previously chemically activated. Photoluminescence (PL) spectra were registered at room temperature by using as photoexcitation the 325 nm He-Cd line. The PL versus the photon energy emission curves peak at around 3.2 eV, which open the possible application of this material for solid state UV laser devices fabrication.

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JS1-WeA-P.4 PHOTOLUMINESCENCE AND BAND-SPLITTING IN CDS THIN FILMS, INFLUENCE OF CDCL2 AND THERMAL ANNEALING. O. Vigil-Galán, G. Contreras-Puente, and J. Aguilar-Hernández. Escuela Superior de Física y Matemáticas, Instituto Poli-técnico Nacional, México 07738 D.F. J. Vidal-Larramendi, and A. Arias-Carbajal. Univ. de la Ha-bana, 43100, La Habana, Cuba. O. Zelaya-Angel. Departamento de Física, CINVESTAV-IPN, P.O. Box 14-740, México 07360 D. F.

CdS thin films were deposited on conducting glass substrates by three different techniques: (a) chemical bath deposition (CBD), (b) close spaced vapor transport (CSVT), and (c) laser ablation (LA). As-grown and coated with CdCl2 CdS-samples were thermal treated (TT) in Ar. From optical absorption measurements the valence band splitting in cubic and hexagonal layers are observed (in CBD and CSVT films). In the case of CdS films grown by CSVT the hexagonal wurtzite (W) crys-talline phase is observed in as-grown and TT samples, while using CBD as-grown and annealed CdS films are cubic zincblende (ZB). For LA-CdS samples no band splitting was observed in both as-grown and annealed samples, these two types of LA-CdS layers have W as crystalline phase. Band splitting is characterized for the variation of the energy band gap (Eg) shift (ΔEg) due to the spin-orbit interaction with ΔEg = 0.069 eV, where ΔEg → *

gEΔ when ZB → W, with *gEΔ = 0.081 eV, the

change is owing to the reordering of splitting levels because of the addition of the crystal field inter-action. The evolution of the crystalline quality and the ΔEg change in the three kinds of grown films, beside optical absorption measurements, was studied from photoluminescence spectra

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JS1-WeA-P.3 OPTICAL CHARACTERIZATION OF VACUUM EVAPORATED CdZnTe THIN FILMS DEPOSITED BY STACKED LAYER METHOD. G.G. Rusu, M. Rusu, M. Girtan. Faculty of Physics, “Al.I. Cuza” University, B-dul Carol I, No. 11, Iasi, Romania (e-mail: [email protected])

The interest in the study of CdZnTe (CZT) alloys in thin films has been increased due to their impor-tant applications in technology of thin film devices as solar cells, photo-detectors, gamma-ray detec-tors, etc. Among other preparation techniques of CZT, the physical vapour deposition is often preferred. In such method, the evaporation of CdTe and ZnTe mixed powder or co-evaporation from dual CdTe and ZnTe sources are frequently used. An inconvenient of these procedures is the difficulty to con-trol of Zn content in as evaporated CdZnTe films due to the vapour pressure difference between CdTe and ZnTe and to the lower sticking coefficient of Zn. To avoid this inconvenient, in present paper, a modified two source evaporation technique was used to prepare CdZnTe thin films. Namely, during film deposition, the film substrates, placed onto a ro-tating disk, passed successively with constant rate over the CdTe powder and metallic Zn evapora-tion sources respectively, separated between them by two glass cylinders. In this way, nanolayered CdTe/Zn structures with uniform Zn content were deposited. The structural and optical properties of as deposited CdZnTe films were investigated. Depending on the preparation conditions, both quasi-amorphous and oriented (111) polycrystalline films were obtained. Also, depending on Zn content and heat treatment, the value of optical band gap, Eg, for studied films ranged between 1.48 eV and 1.63 eV.

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JS1-WeA-P.2 STUDY OF OPTICAL PROPERTIES OF DIAMOND LIKE CARBON /POROUS SILICON ANTIREFLECTION COATING LAYERS FOR MULTICRYSTAL-LINE SILICON SOLAR CELL APPLICATIONS. K. Ait-Hamouda. Labo Instrumentation, Faculté d’Electronique et informatique, USTHB, BP 32 El-Alia Bab-ezouar Alger, Algérie. M. Ouchabane. CDTA , Haouche Loukil BP17, Baba-Hassen Alger, Algérie. A. Ababou. Labo Instru-mentation, Faculté d’Electronique et informatique, USTHB, BP 32 El-Alia Bab-ezouar Alger, Al-gérie. N. Gabouze. UDTS, 2Bd Frantz Fanon BP 399, Alger Algérie

In the past decade, Diamond Like Carbon (DLC) coatings have received great attention essentially due to their unique properties such as mechanical hardness, adhesion strength and chemical inert-ness, and recently in the sensing application, combined with porous silicon. In addition, the same research group demonstrates an enhancement of the photoluminescence of the porous layer subjected to a DLC layer deposition. In this work, we report a study on some optical properties of DLC films. The DLC films have been deposited by DC discharge plasma enhanced chemical vapor deposition. The deposited layers have been characterized by spectrophotometry, ellipsometry and FTIR analysis. The evolution of optical properties for different DLC thickness layers has been correlated with the FTIR spectra change. In addition, The DLC films have been deposited on multicrystalline solar cell with a PS film (< 0.3 μm) as an antireflection coating. The results reveal that the solar cell efficiency strongly depends on the DLC layer thickness. The quantum efficiency of the solar cell coated with a DLC layer increases by 5% order than the uncoated cell.

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JS1-WeA-P.1 γN -SHIFTING AS A FUNCTION OF N2 CONTENT IN AISI 304 NI-TRIDING. R. Valencia-Alvarado a, A. de la Piedad-Beneitez , J. de la Rosa-Vázquez , R. López-Callejas , S. R. Barocio , O. G. Godoy-Cabrera , A. Mercado-Cabrera , R. Peña-Eguiluz and A. E. Muñoz-Castro. Instituto Nacional de Investigaciones Nucleares, Plasma Physics Laboratory, A P. 18-1027, 11801 México, D.F. Instituto Tecnológico de Toluca, AP 890, Toluca, México. Insti-tuto Politécnico Nacional, ESIME, 07738, México, D.F. a E-mail: [email protected] We present in this work some experimental results obtained from nitriding AISI 304 stainless steel at different temperatures by means of RF/DC generated 1015-1016 m-3 density plasmas in the 1-4 eV temperature range. The samples were biased up to –500 V. Substrate temperatures proof to be an influential factor in the diffusion of the impinging ions into the material under treatment. In turn, this temperature during the expanded γN shift, is a function of the amount of nitrogen introduced to the sample given by the bias, the depth of the nitrided layer and the plasma characteristics. Thus, we have chosen the substrate temperature as a global control variable in order to analyze the evolution of the nitrogen enrichment process through its influence on the X ray diffraction imaging of the γN shift in the samples. The optimization of the temperature is explored along with its limits in terms of the Cr precipitation threshold.

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RIVA-TF-WeA-P.7 GROWTH OF CRYSTAL GERMANIUM-CARBIDE BY IMPLAN-TATION . Genene Tessema1,2 1Faculty of Science, Department of Physics, Addis Ababa Univer-sity, P.O.BOX 1176, Addis Ababa, Ethiopia. 2Helmholtz-Institut für Strahlen und Kernphysik, Nus-salle 14-16, 53115 Bonn, Germany The interactions of carbon with probe nucleus 111In have been studied in germanium using the per-turbed angular correlation (PAC) method, which has the ability to detect the microscopic environ-ments of the probe atom by means of the interaction of the nuclear moments of the probe and the sur-rounding electromagnetic fields1,2. At high dose carbon implantation in germanium two complexes have been identified by their unique quadrupole interaction frequencies. An interaction frequency of νQ = 207(1) MHz (η = 0.16(3)) appeared at annealing temperatures below 650οC. Above 650οC, it was replaced by a second interaction frequency of νQ = 500(1) MHz ( η= 0). The frequencies are at-tributed to two different carbon-indium pairs. The orientation of the corresponding electric field gra-dients and thermal stability of the defect complexes are studied. The results are found to be in good agreement with other methods3. 1. Th. Wichert, M. Deicher, G. Grübel, R. Keller, N. Schulz and H. Skudlik, Appl. Phys. A 48, 59 (1989) 2. G. Schatz and A. Weidinger, Nuclear Condensed Matter Physics, John Wiley and Sons, New York (1992) 3. L. Hoffmann, J. C. Bach, and B. Bech Nielsen, Phys. Rev. B ; Vol. 55(17), 11 167 (1997)

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RIVA-TF-WeA-P.6 AgInTe2 CHALCOPYRITE THIN FILMS OBTAINED BY ELECTRODEPOSITION TECHNIQUES AND ANNEALING. R. Díaz, F. Rueda Dpto. Física Aplicada Universidad Autónoma de Madrid, 28049 Madrid, Spain. P.Herrasti, E. Vazquez Dpto. Quí-mica Física Aplicada Universidad Autónoma de Madrid, 28049 Madrid, Spain. M. Abd el Lefdil Dpt de Physique, Université de Rabat, Maroc

In order to obtain single phase thin films of the system Ag-In-Te for thin film solar cell applications, electrodeposition techniques followed by a baking in Te atmosphere were used. For the formation of the precursor films three alternative processes were followed, 1t) the co-electrodeposición of Ag and In, 2d) a layer of Ag with an overlayer of InTe and 3d) a layer of Ag and an overlayer of In. The vacuum annealing were done with a source of Te metal close to the films that allowed to crystallize into ternary chalcopyrite phase the as deposited amorphous films. Bath compositions, deposition potentials and deposition times have been changed to obtain the precursor thin films on substrates of molybdenum supported by glass. In order to determine the optical properties, SnO2 coated substrates were also used. The single phase films are obtained by further annealing in Te atmosphere in the 250-400oC range with different cooling profiles. This annealing strongly affects the Te concentration as well as the In/Ag atomic ratio and the number of phases. Single chalcopyrite phase has been obtained for specific annealing conditions and is related to Te concentration. Composition and X-ray studies have been carried out and several phases of AgInTe2 and In-rich Telluride chalcopyrites have been found. The film morphology and unit cell parameters for single phase samples depend strongly on the composition in the annealed samples. The support of contract No CTQ2005-04469/BQU is acknowledged

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RIVA-TF-WeA-P.5 VAPOUR SOURCE WITH SUBMONOLAYER CONTROL. H. P. Marques, A. R. Canário, O. M. N. D. Teodoro and A. M. C. Moutinho. CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 CAPARICA, Portugal To achieve highly accurate controlled depositions a specially designed vapour source was developed. It provides direct rate and thickness monitoring with submonolayer control. This compact dosing system basically consists of an evaporation source, a quartz crystal microbal-ance and a shutter. The source was intended to evaporate metals with low to medium melting tem-perature. It was tested with a high purity Ag wire (99.99%) wrapped around a tungsten filament. Re-sistive heating was provided by an adjustable constant current through the filament. The microbalance and the surface are mounted on the same line with the filament in between. The careful geometric configuration and distances of the microbalance, filament and surface are such that only 1/10th of the amount of metal deposited on the quartz crystal is deposited on the sample sur-face. Therefore the resolution of the microbalance is extended by one order of magnitude. The direct thickness measurement by the quartz microbalance with factory parameters was checked in a calibration experiment. For the calibration an Ag film was deposited on polycrystalline Au sur-face and the growth followed with LEIS. The break at the monolayer formation was used to calibrate the thickness measurements. This source is being successfully used to study the growth of Ag clusters on TiO2. The deposition rate is a known parameter to control the size of the nanoclusters. During the depositions the me-chanical shutter provides an accurate vapour blanking to the surface. The typical dosing rate may be as low as 0.035 ML/min, where 1 ML corresponds to 1.4x1015 atoms.cm-2.

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RIVA-TF-WeA-P.4 NITROGEN-DOPED TiO2 THIN FILMS DEPOSITED ONTO ITO/GLASS SUBSTRATES. Diana Mardare. Al.I.Cuza University, Faculty of Physics, Carol I Blvd., No.11, Iasi 700506, ROMANIA. Luca Dumitru. Al.I.Cuza University, Faculty of Physics, Carol I Blvd., No.11, Iasi 700506, ROMANIA Titanium dioxide films are extensively used in optical thin film device applications owing to their appropriate optical properties, high thermal and chemical stability in hostile environments. These films present good durability, a high transmittance in the visible spectral range, and a high refractive index, so that they are suitable for applications, such as: antireflection coatings, multilayer optical coatings (used as optical filters), optical waveguides, etc. Also, TiO2 has focussed a considerable at-tention in the past decades as a material with a strong oxidation power, being considered one of the best photocatalytic material which can be used in order to solve some of the world environmental problems. Titanium oxide crystallizes in three different forms: anatase (tetragonal), rutile (tetragonal) and brookite (orthorhombic) and may also exist in an amorphous state. Rutile is a denser phase than ana-tase and brookite, being also the most thermodynamically stable. By changing the deposition pa-rameters, by performing a heat treatment, or by doping with different impurities, the ratio of the mentioned phases changes, leading to changes in optical and electrical properties of titanium oxide thin films [1-3]. The three phases are characterized by different optical properties and determine dif-ferent transmittances, optical constants and optical band gaps of the thin films. The catalytic proper-ties are connected with the large band gap value of the anatase phase (3.2 eV) associated with a low recombination rate of the charge carriers generated in the surface area by the incident photons. Undoped and nitrogen-doped titanium oxide films were prepared by reactive magnetron sputtering onto ITO/glass substrates. Film structure and surface morphology were investigated by X-ray dif-fraction and atomic force microscopy. X-ray diffraction (XRD) studies revealed an amorphous struc-ture of the as-deposited thin films. The surface roughness was derived from AFM imaging. By heat treatment the amorphous films became polycrystalline. The heat-treated-nitrogen-doped films have a pure anatase structure, while the undoped ones contain only the rutile phase. The contact angle of the deionized water with film surface was monitored during both photoactiva-tion and recovery regimes. The results are discussed in terms of the effects of surface roughness and of rutile-anatase TiO2 phase transformation induced by heat treatment and by nitrogen doping, as re-flected in optical transmittance results. [1] D. Mardare, M. Tasca, M. Delibas and G. I. Rusu, Appl Surf Sci 156 (2000) 200. [2] A. R. Bally, E. N. Korobeinikova, P. E. Schmid, F. Lévy and F. Bussy, J Phys D: Appl Phys 31 (1998) 1149. [3] D. Mardare and P. Hones, Mater Sci Eng B 68 (1999) 42.

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RIVA.TF-WEA-P.3 ON THE PHYSICAL PROPERTIES OF PENTACENE THIN FILMS. Mihaela Girtana,b Sylvie Dabos – Seignona, J.M. Nunzia. aLaboratoire POMA, UMR CNRS 6136, Université d’Angers, 2 Bd. Lavoisier, 49045 Angers cedex, France, email: [email protected] Faculty of Physics, Al.I. Cuza University of Iasi, Romania

Pentacene thin films with thickness ranged between 50 nm and 200 nm were deposited by vacuum thermal evaporation on glass and ITO substrates at room temperature. The rate of deposition was about 0.14 nm/s. The influence of substrate nature and films thickness on the film morphology was investigate by atomic force microscopy (AFM). Electrical and optical investigations were correlated with the structural and morphological analyses.

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RIVA-TF-WeA-P.2 PHOTOCATALYTIC DEGRADATION OF COMMERCIAL DYES USED IN THE TEXTILE INDUSTRY BY THE DEPOSITION TiO2 THIN FILMS ON GLASS SUBSTRATES. S.M. Marques1, C.J. Tavares1, V. Teixeira1, J.O. Carneiro1, A.J. Fernan-des2. 1Departamento de Física, Universidade do Minho, 4800-058 Guimarães, Portugal. 2Departamento de Física, Universidade de Aveiro, 3810-193 Aveiro, Portugal [email protected]

The interest in nanoparticle photocatalytic titania (TiO2) thin films has been increasing over the last few years, due to the self-cleaning nature of these coatings. They have been used on industrial appli-cations, mainly due their ability to degrade pollutants dissolved in water. Titania acts as a photo-catylist for the dissociation of organic impurities on a particular surface, such as glass. The driving force behind this photocatalisation is simply ultraviolet (UV) light and atmospheric oxygen. The thin films of titania were deposited by unbalanced reactive magnetron sputtering, from a high purity Ti target in an Ar/O2 atmosphere, with an argon flow rate of 60 sccm (working gas) and a variable oxy-gen flow rate in he range of 1.5-9 sccm (reactive gas). Due to the fact that the deposition temperature is rather low (≈ 200ºC), the titanium dioxide particles that nucleate on the substrate do not have suf-ficient energy and mobility to crystallise in a regular lattice, such as Brookite, Anatase or Rutile. In order to achieve this thermodynamical equilibrium and enhance the composition between the crystal-lographic phases, after deposition the samples were thermally annealed in a high vacuum furnace at different temperatures, 300ºC, 400ºC and 500ºC for 2 hours. In order to comprehend the underlying structure, X-ray diffraction measurements were then preformed in these heat treated samples and the composition of the films was study by Rutherford Backscattering spectroscopy (RBS). We also esti-mated the thickness of the films made with different flow rates of oxygen and with different times of deposition, using the Swanepoel’s method for the calculation of the optical properties of the coat-ings. The photocatalytic behaviour of the titania coatings was assessed by combined ultra-violet irra-diation and absorption measurements of particular dyes. The observed photo-decomposition of the aqueous solution (organic pollutants) was measured in the UV/Vis Spectrum by the decrease of the maximum absorbance with irradiation time. The colour of the dye becomes colourless during this process, hence indicating that the chemical oxidation-reduction mechanisms abound on the surface of the titania films. As pollutants, we used dyes that are currently used in the textile industry, as it is the case of the reactive dye “RED 41”.

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RIVA-TF-WeA-P.1 SEM AND XPS ANALYSIS OF POLYCRYSTALLINE GAN FILMS GROWN BY CYCLIC PULSED LASER DEPOSITION. P. Sanguino1, R. Schwarz1. 1 Depar-tamento de Física, Instituto Superior Técnico, Lisboa, Portugal M. Wilhelm2, M. Kunst2 2 Hahn-Meitner-Institut, Solare Energetik, Berlin, Germany O. Teodoro3 Departamento de Física, Universi-dade Nova de Lisboa, Monte de Caparica, Portugal

We describe a detailed study of Scanning Electron Microscopy (SEM) combined with Energy Dis-persive Spectroscopy (EDS) analysis to study composition and structure of 500 nm thick polycrystal-line GaN samples. The films have been deposited by Cyclic-Pulsed Laser Deposition (Cyclic-PLD) with a Nd:YAG nanosecond pulsed laser at 1064 nm. SEM pictures of the GaN layers revealed a structure composed of grains with typical dimensions of 200 nm. Coalescence of the grains was more evident for a 1 �m thick sample. EDS mapping of the GaN layer was performed for Ga, N, O, and Al and could be related with the corresponding SEM scan. Both EDS and XPS composition analysis pointed to a Ga rich (or N deficient) GaN layer.

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RIVA-SS-WeA-P.3 ELECTRON STIMULATED DESORPTION STUDY OF DEFCT SITES ON THE MgO(100) SURFACE USING QUADRUPOLE MASS SPECTROMETRY AND TIME OF FLIGHT. I. Colera*, J. L. de Segovia**, D. Cáceres*, E. Román** and R. Gon-zález*. * Departamento de Física. Universidad Carlos III de Madrid. Leganés. 28911 Madrid. Spain.**

Laboratorio de Física e Ingeniería de Superficies. Instituto de Ciencia de Materiales. CSIC.Cantoblanco. 28049 Madrid. Spain While the quadrupole mass spectrometer (QMS) is an excellent tool to identify desorbed ions and energy thresholds in electron stimulated desorption (ESD) experiments, its analysis of the ion ki-netic energy distribution is questionable. However, time of flight (TOF) is an excellent technique to analyse the ion energies by using the QMS as the driving tube for the time of flight. The simultane-ous use of the ESDQMS and ESDTOF techniques yields excellent results in the determination of the ion nature, ion threshold, and ion energy distribution in the study of site defects of on the MgO(100) surface. Defect sites are identified by exposing the MgO(100) surface to D2O and H2

18O. Thus, the D and 18O can be differentiated from the 16O and H surface atoms. The energy of the exploring elec-trons varied from 200 to 600 eV, and an intensity of 100 nA was used to avoid surface damage. The sample charge was also studied as a function of the incident electron en energy.

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RIVA-SS-WeA-P.2 SECONDARY ELECTRON EMISSION YIELDS OF EXTER-NAL DIELECTRIC COATINGS USED IN SPACE . Isabel Montero, Ainhoa Pardo, Pablo Rios and José Luis de Segovia. Instituto de Ciencia de Materiales de Madrid. CSIC. Cantoblanco. 28049-Madrid. Spain. Luis Galán. Universidad Autónoma de Madrid. Cantoblanco. 28049-Madrid. Spain. Léon Lévy. Office National d'Etudes et de Recherche Aerospatiales, 2 Avenue Edouard Belin, 31055 Toulouse, Cedex 4, France. Marc Van Eesbeek. European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Keplerlaan 1, PO Box 299, NL-2200 AG Noord-wijk, The Netherland

Within ESA Program, AO4136 “Material Characterisation for Plasma Interaction Analysis”, headed as prime contractor by ONERA, our group from ICMM (CSIC) and UAM has been developing a re-search on secondary electron emission and photoemission properties of reliable insulator materials to study their charging behaviour in space. The spacecraft surface potential is a function of the net current flow to or from the spacecraft sur-face. Electrons impinging on the spacecraft can produce secondary electron emission. Photoemission from the extreme ultraviolet photon range is the most important since in that region many materials have rather large photoelectric yields and the solar spectrum also has significant energy there. This work presents results on secondary electron emission and photoemission yields of space used exter-nal dielectric coatings. The dielectric materials studied was polymers: kapton, betacloth and upilex, and doped silicon glasses: CMX and CMO. The total secondary electron emission coefficient, σ, per primary electron, versus primary energy, Ep, curve was characterized by the following parameters: σm the maximum value and the corre-sponding primary energy Em, and the two crossover energies: E1, the lowest Ep for σ =1, and E2 the highest Ep for σ =1. The beam pulsing measuring technique was used in order to reduce or avoid the charge incorporation into the samples. SEY was measured for normal incidence and as a function of primary electron energy. Current pulses of 0.1 -1 μs of low intensity (1nA-50 nA) were used to re-duce the electron dose received by the sample (≤106electrons/pulse). For each primary energy, the sample was bombarded with only one current pulse. Surface charge decay occurs immediately when the e-irradiation is stopped, but it depends on the discharging time constants. After each measure-ment, the charge of the sample was removed: the trapped charge was liberated with the mercury lamp (negative surface charging) and the flood-gun (positive surface charging). Analysis of the coat-ings was performed, apart from SEY and PES measurements, by XPS (X-ray Photoemission Spec-troscopy), SEM (Scanning Electron Microscopy), EDX (Energy Dispersive X-ray Spectroscopy) and UVS (Ultraviolet spectroscopy).

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RIVA-SS-WeA-P.1 TiCr ALLOYS OF LOW SECONDARY ELECTRON EMISSION FOR ANTIMULTIPACTOR APPLICATIONS. G. G. Fuentes and R. J. Rodríguez, AIN-Centro de Ingeniería Avanzada de Superficies, Cordovilla, 31191, Pamplona, Spain. L. Galán, Departa-mento de Física Aplicada. Universidad Autónoma de Madrid. Cantoblanco. 28049-Madrid. Spain. I. Montero and J. L. Segovia, Instituto de Ciencia de Materiales de Madrid. CSIC. Cantoblonco. 28049-Madrid. Spain TiCr alloys of low secondary electron emission have been investigated as potential anti-multipactor coatings. Cathodic-arc evaporation technique in Ar atmosphere was used. The ion energy can be controlled by the substrate biasing. Chemical state analysis and surface composition were obtained by X-ray Photoemission Spectroscopy (XPS). Depth profiling was performed by Glow Discharge Optical Emission Spectroscopy (GDOES). Scanning Electron Microscopy images show the forma-tion of grains on the surface. The film composition is homogeneous, however, the composition of the grains varied with their size. Larger grains are richer in titanium, while small ones are rich in chro-mium as indicated by energy Dispersive X-ray analysis. Total secondary electron emission yield was determined by measuring the sample current to ground when bombarded by a primary electron beam of determined energy. The secondary electron emission coefficient of TiCr alloy exposed to air was lower than those of chromium or titanium coatings and their nitrides. The experimental secondary emission yield values together with a Montecarlo model of the secondary emission process were used to obtain the multipactor threshold.

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JUNE 28 WEDNESDAY MORNING

WS-18-WeM-INV.12 THE EFFECT OF MECHANICAL AND FRICTIONAL PHE-NOMENA ON THE QUALITY OF VACUUM IN ADVANCED TECHNOLOGIES. R.A. Nevshupa. Department of Vacuum Mechanics and Tribology (MT-11), Bauman Moscow State Technical University, 2-Baumanskaia 5, Moscow 105005, Russia. J.L. de Segovia, E. Roman. De-partment of Surface Physics and Engineering, Institute of Material Science of Madrid, C/ Sor Juana Ines de la Cruz 3, Cantoblanco, Madrid 28049, Spain By the last quarter of the twentieth century, as the result of several progresses in materials, coatings, degassing procedure, and pumping technologies, attaining of extremely high vacuum below 10-8 Pa had became almost routine task in many technologies ranging from electronic and optoelectronic in-dustries to large particle accelerators and physical experimental systems. These progresses allowed to control precisely desorption of gases from stationary surfaces faced to vacuum and to obtain spe-cific desorption rate from these surfaces below 10-8 Pa·m3·m-2·s-1. In this circumstances secondary desorption phenomena come to the foreground to provide quality of the total and partial pressures in technological systems. Tribodesorption, i.e. desorption of gas stimulated by mutual friction, indenta-tion and other types of mechanical action, is one of the most important among these desorption phe-nomena due to high desorption yield and abundance of moving parts in modern ultrahigh vacuum technological equipment. Specific desorption rate during sliding of stainless steel, other metals and tribological coatings can be as high as 10-2 - 10-3 Pa·m3·m-2·s-1. Although contact area, which mole-cules are desorbed from, is usually very small, instant pressure increase due to translation of moving parts inside vacuum system can be of the order of 10-6 - 10-7 Pa that is critical for many technological processes. Moreover, friction is a source of hydrocarbons, carbon oxides, water vapours and other contaminating substances, which might harm sensitive production. Tribodesorption is a complex phenomenon based on three main physical sources: desorption of the topmost adsorbed gas layers, emission of gas molecules from the shallow subsurface zones and tri-bochemical reactions. In high and ultrahigh vacuum the late two sources are dominating. The com-position of desorbed gas depends on many factors including kind of material, content of the gas in the material, presence of adsorbed phases and so on. Time behaviour of tribodesorption has maxi-mum at the beginning of friction of fresh surface and slowly decreases during friction. However, tri-bodesorption rate can be restored after resting time during 12 or more hours or after moderate heat-ing of the rubbed surface. These facts point the diffusion of gas atoms and molecules in the material bulk as a precursor of tribodesorption. In addition, tribodesorption is strongly correlated with any damage of the surface, i.e. plastic defor-mation, fracture, cracking, wear and so on. This feature is very promising for developing of reliable tribological coatings for vacuum applications.

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WS-18-WeM-INV.11 QA EFFORTS IN MANUFACTURING LARGE CRYOPUMP SYSTEMS FOR NUCLEAR FUSION APPLICATION. Hans S. Jensen and Chr. Day. Institute for Technical Physics, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany. Forschungszentrum Karlsruhe (FZK) is contributing to the ITER (Latin: The way) project, the next generation fusion machine. ITER is the experimental step between today’s studies of plasma physics and tomorrow's electricity-producing fusion power plants. It is an international project involving many Associations from all over the world. The philosophy of the ITER construction, which is planned to be ready in ten years from now, is based on in-kind contributions. This means that each Association is actively taking responsibility for the components it provides to ITER: responsibility in cost, time, compliance to the Technical Specification, and quality. Within the general Quality Assur-ance framework which is set by the ITER Legal Entity, there is quite some flexibility left for the in-dividual Association as to how fulfil quality aspects for the specific component; this approach is typical for a big R&D project, such as ITER, involving many prototypical components. For-schungszentrum Karlsruhe is expected to become the leading Association for provision of the large tailor-made cryopumping systems for ITER. This talk exemplifies the FZK experiences of manufacturing and the related quality assurance man-agement for a recently accomplished R&D project, namely for a cryosorption pumping system used in a test facility of a neutral beam injector that will be used to heat the plasma of a nuclear fusion re-actor with a beam of deuterium or hydrogen molecules. The huge gas throughput into the vessel of the test facility results in challenging needs on the cryopumping system, comprising two identical tailor-made pumps. To establish a mean pressure of several 10-5 mbar in the test vessel a pumping speed of about 350 m3/s per pump is needed. This was realized with charcoal coated cryopanels which effectively pump hydrogen. For the cooling of the cryopanels, liquid helium at saturation pressure is used and therefore a two-phase forced flow in the cryopump system must be controlled. FZK received the responsibility to design, build, install and test the hardware for this task. The FZK specified requirements, detailed in 11 individual technical specifications which each included strict QA requirements. The manufacturing of the components were placed with a large number of indus-trial companies within Europe. The central contract for the assembly of the cryopumps was placed with an industrial company with experience in manufacture of advanced scientific components. This Main Assembly Contractor (MAC) manufactured the cryopumps using FZK design and drawings, but MAC also received a number of special components as FZK free issue items, where FZK was re-sponsible for the testing and quality control before, during and after the manufacture. This presentation begins with a short outline of the cryopumping system design. It then identifies the FZK activities during some of the manufacturing processes, in particular the Third Party pre-manufacturing approval, construction approval, inspection of approved materials, checking welders´ qualifications, signing quality plans, witnessing the pressure testing, witnessing the vacuum leak test-ing, etc. The vacuum integrity of the different circuits is of paramount importance and vacuum leak testing has been included as holding points in the Quality Plan. All components have been tested to <10-9 mbar/l/sec He and all components have been produced from certified materials. The presenta-tion will be concluded by illustrating some of the problems during the manufacturing process and sound advice in optimizing the quality standard is given.

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WS-18-TuA-INV.10 SPANISH SYNCHROTRON RADIATION: SOURCE: PRO-JECT STATUS AND VACUUM SYSTEM. Ll. Miralles and E. Al-Dmour. CELLS, Barcelona. Spain The Storage Ring ALBA is a 3 GeV third generation synchrotron light source under construction in Barcelona (Spain). ALBA is optimized for high photon flux density with a beam emittance of 4.5 nm.rad and a large number of straight sections for Insertion Devices (3´ 8 m, 12´ 4.2 m and 2´ 2.6 m) in a relatively small circumference of 268.8 m. Top-up operation is foreseen from the start. The in-jector complex will consist of a 100 MeV Linac and a full energy Booster with a rather small emit-tance 9nm.rad. The design of the lattice and of the major components of the accelerator complex (Linac and Booster, Magnets, RF system, Vacuum system) has been completed and the procurement procedure has started for the large majority of them. The construction of the building is planned to start in the first half of 2006 and the commissioning of the storage ring is foreseen for the end of 2008. This report gives an overview of the status of the project.

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WS-18-WeM-INV.9 PHYSICAL AND TECHNOLOGICAL ASPECTS OF MEMS VAC-UUM PACKAGING. F. Völklein, A. Meier, FH Wiesbaden, University of Applied Sciences. Am Brückweg 26, D-65428 Rüsselsheim, Germany

The realization of Micro Electro Mechanical Systems (MEMS) or Micro Opto Electro Mechani-cal Systems (MOEMS) requires sofisticated fabrication technologies based on thin film deposi-tion, photolithography and etching techniques. MEMS fabrication can be divided into three major groups: i) fabrication with additive and subtractive processes on the wafer level ii) packaging, involving processes such as bonding, lead attachment and encapsulation in a pro-

tective body or in cavities with reduced gas pressure (vacuum) iii) testing, including package leak test, electrical integrity and MEMS functionality. The last two process groups incorporate the most costly steps. MEMS packaging is more difficult and expensive than packaging of Integrated Circuits (IC) and may be totally different (e.g. for gas sensors) from IC housing. MEMS vacuum packaging is required for accelerometers in order to optimize the damping of the de-vices. High-Q micro resonators might need a good vacuum. Mechnical vacuum sensors using pie-zoresistive or capacitive measuring effects include small cavities (volumes in the order of 1 mm³) with reduced reference pressure or vacuum. Cavity sealing can serve as a batch-compatible packaging technique by encapsulating a chip feature or whole chip at a time. Chip features can be sealed by surface micromachining using Polysilicon or Silicon Nitride deposition techniques and sacrificial layer technology. Such micromachined surface packages (microshells) are much smaller than typical bulk MEMS packages. Microshells can be made by defining thin gaps (100 nm) between the substrate and the perimeter of the structural ele-ments by etching away a sacrificial layer sandwiched between the two and then sealing the resulting gaps. In so-called reactive sealing thermal oxidation of the Polysilicon and Si-substrate seals the nar-row openings left after removal of the spacer phosphosilicate (PSG) sacrificial layer. Alternatively, sealant films, such as oxides and nitrides, can be deposited over small etchant holes. The first com-mercial absolut Polysilicon pressure sensor incorporates such a reactively sealed vacuum shell. Epi-taxial cavity sealing and HEXIL cavity sealing are alternative technologies. These and other lithog-raphy-defined packages, such as those involving ultraviolet patternable polymers, might be an inte-gral part of the overall fabrication processs and lend to inexpensive batch solutions. In bulk micromachining and Si fusion-bonded (SFB) surface micromachining, cavities are fabricated by bonding, respectively, a glass plate (anodic bonding) or a Si wafer (fusion bonding) over etched cavities in a bottom Si wafer. Field-assisted thermal bonding (anodic bonding, also known as elec-trostatic bonding) can be established between a sodium-rich glass and Silicon at relatively low proc-ess temperatures. This method is mostly applicable to wafer-scale chip bonding. SFB is performed between flat Si wafers with slightly oxidized surfaces. When incorporating an intermediate layer be-tween two substrates, many thermal vacuum bonding techniques are feasible. Silicon microstructures can be sealed together by eutectic bonding, e.g. Au-Si eutectic bonding at 363°C. The most impor-tant problems of MEMS vacuum packaging are the very small volumes of cavities combined with the outgassing during the sealing process. Long term stable vacuum in microcavities can be realized by using thin getter layers and sealing materials with low permeation coefficients.

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JS2-WeM-OR.5 DECORATIVE COATINGS OF TITANIUM OXIDE OBTAINED BY PVD. J.A. García, R. Martínez. M. Rico and R.J. Rodríguez. Asociación de la Industria Nava-rra. C/San Cosme y San Damián s/n, Pamplona 31191 Spain.Email: [email protected] In the last years PVD techniques have strongly emerged in the European market of the decorative coatings. Faucets and other bath accessories are actually been coated with ceramic films like TiN (golden yellow) and TiCN (brass) with excellent reproducibility and corrosion resistance, but the use of these kind of hard coatings just provide a limited list of metallic colours. In the recent years a wider colour range are been achieved using optical interference phenomena by depositing nanometric metal Oxide films. It is possible to obtain different colours by controlling the final thickness of the oxide layers. This article gathers the research to obtain different interference colours, reports the obtained reflectance curves and tries to find the relations between the oxide thickness measures by Glow discharge optical emission spectrometry with the colour parameters measured with a spectrophotometer. Microstructure and thickness had also been measured by using field emission scanning electron microscopy. As conclusion we can demonstrate that the final colour is the results of the destructive interference, depending of the relation between the wave length of the colour and the thickness of the oxide film. Keywords. Decorative coatings, Interference colours, GDOES, FESEM

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JS2-WeM-OR.4 HARDNESS AND TRIBOLOGY MEASUREMENTS ON ZrN COAT-INGS DEPOSITED BY REACTIVE SPUTTERING TECHNIQUE. M. A. Auger. Departa-mento de Física. Universidad Carlos III. Avda. de la Universidad, 30. 28911 Leganés, Madrid. Spain. J. J. Araiza. Unidad Académica de Física. Universidad Autónoma de Zacatecas. Avda. Prepa-ratoria Nº 301. Fracc. Progreso. Zacatecas, Zac. 98000 Méjico. C. Falcony. Departamento de Física. CINVESTAV-IPN. Aptdo. 14-740. Méjico D.F. 07360 Méjico. O. Sánchez and J.M. Albella. Depar-tamento de Física e Ingeniería de Superficies. Instituto de Ciencia de Materiales de Madrid-CSIC. C/ Sor Juana Inés de la Cruz, 3. 28049 Cantoblanco, Madrid. Spain. Thin films based on transition metal nitrides have been widely used in many applications because of their interesting properties (mechanical, tribological, chemical stability, etc.) together with their shiny and golden appearance, which make them highly attractive for applications as protective and decorative coatings in different industrial and commercial sectors. In this work, a series of ZrN coatings have been grown in a rf sputtering deposition chamber, where different ratios of Ar/N2 gases (5/1, 5/5, 1/5 sccm) were introduced during the process as a reactive atmosphere. Once deposited, the coatings were thermally treated in a 500oC oxygen atmosphere try-ing to promote the oxynitride formation (ZrNO), which has been proposed as a suitable material for being used as optical and decorative coatings. Due to the incorporation of oxygen to the matrix of covalent metal-nitrogen bonds, the electronic properties are modified giving place to interesting changes in the colour range of the coatings, thus allowing the control of the surface appearance in decorative applications. The chemical composition, mechanical and tribological properties of the as-deposited and thermally treated samples have been measured by different techniques: EDX, nanoindentation and pin-on-disk techniques respectively. ZrN samples grown at 5 sccm Ar + 1 sccm N2 showed a composition close to the stoichiometry, and offered the best mechanical and tribology behaviour. These samples, after being subjected to the oxygen thermal treatment, improve even more their hardness, making them more suitable for protective and decorative purposes.

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JS2-WeM-OR.3 TRIBOLOGICAL CHARACTERIZATION OF TUNGSTEN NITRIDE COATING AT ELEVATED TEMPERATURE. T. Polcar, N.M.G. Parreira and A. Cavaleiro a*. ICEMS – Grupo de Materiais e Engenharia de Superfícies, Faculdade de Ciências e Tecnologia da Universidade de Coimbra – Pólo II, 3030-201 Coimbra, Portugal. * To whom all correspondence should be addressed ([email protected])

Transition metal nitrides are known for the unique combination of excellent mechanical properties (hardness and Young’s modulus), high melting point, good chemical stability and high electrical conductivity. However, tungsten nitrides still stand aside of the main attention, particularly compared to titanium or chromium nitrides. The first studies of tungsten nitrides thin films were performed, ba-sically, for electronic applications such as, semiconductors or diffusion barriers. In the 90´s, W-N coatings were started to be studied for mechanical applications and further studies were performed on the addition of different elements (e.g. W-Ti-N and W-Si-N) in order to improve their mechanical properties. There are only few studies dealing with tribological properties of tungsten nitrides and showing their good wear resistance. In our previous study, tungsten nitride coatings with different ni-trogen content showed excellent wear resistance in case of sliding against ceramic Al2O3 and Si3N4 balls. However, many engineering applications require good tribological properties, particularly wear resistance, at elevated temperature. Thus, the present study is focused on the tribological behaviour (friction coefficient and wear rate) of tungsten nitride coating at temperature in the range 20 - 600°C. The structure, hardness, friction and wear of tungsten nitride coating prepared by dc reactive magne-tron sputtering were investigated. The tribological tests were performed on a pin-on-disc tribometer in terrestrial atmosphere with Al2O3 balls as sliding partner. The wear tracks and the ball wear scars were investigated by scanning electron microscopy in order to characterize the dominant wear mechanisms. The coating wear rate was negligible up to 200°C exhibiting a decreasing tendency; however, the wear dramatically increased at higher temperatures. The coating peeled off after the test at 600°C.

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JS2-WeM-INV.2 TRIBOLOGICAL CHARACTERIZATION OF METAL CAR-BIDE/AMORPHOUS CARBON NANOCOMPOSITES: FROM MACRO TO THE MICRO-SCALE. J.C. Sánchez-López*, D. Martínez-Martínez, C. López-Cartes, A. Fernández. Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Avda. Américo Vespucio 49, 41092-Sevilla, Spain. *E-mail: [email protected] The design of multilayered and nanocomposite coatings structures have allowed to achieve superior hardness, toughness and excellent wear resistance useful for many industrial applications. The opti-mization of the tribological performance of such materials represents a challenge as depends not only on factors intrinsic to the coatings (chemical composition, microstructure, phase composition, tex-ture…) but, besides, others related to the application conditions (adhesion to the substrate, nature of the counterfaces, environment, load, etc.). In this work, we review the results obtained for nanocom-posite coatings made of nanocrystalline metal carbides and amorphous carbon (a-C) prepared by PVD techniques. Their characterization appears complicated mainly due to the lack of long-range order and the heterogeneity in chemical compositions at the nanometric scale. The nanocrystal-line/amorphous ratio appears to be a key-parameter to control the tribological properties and its quantification results always not easy. Focusing mainly in the TiC/a-C system prepared by magne-tron sputtering as example, it is showed how the investigation of chemical and structural features at the micro-scale help to determine the aspects influencing the tribological performance at the macro-scale. By varying the power applied to each target (titanium or graphite), it was possible to prepare a wide family of film structures covering from a quasi-polycrystalline TiC to a nanocomposite formed by nanocrystals of TiC. The microstructure of one coating, shown in Fig. 1, reveals a nanometric grain boundary network around TiC crystals of 5 to 10 nm. A complete characterization has been ac-complished by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron mi-croscopy (TEM), electron diffraction and electron energy-loss spectroscopy (EELS) and X-ray pho-toelectron spectroscopy (XPS), pin-on-disk and nanoindentation measurements. EELS and XPS techniques are demonstrated to be very appropriate tools for the estimation of the amorphous phase inside the nanocomposite because they are sensitive to the bonding environment. In the Fig. 2 it is depicted the modification of the shape and position of the C K-edge for different coatings when the contents of TiC and a-C are varied. The increment of the TiC contribution is accompanied by a grad-ual rise of the friction coefficient due to the lack of sufficient amorphous lubricant phase. Combining the complementary information given by the different techniques it was possible to obtain a mapping of the tribological and mechanical properties as a function of the synthesis conditions that helps in the selection of the best coating for specific applications.

Fig. 1: HRTEM image for a TiC/a-C film

Fig. 2 C K-edge EELS spectra and associated friction values for different TiC/a-C coatings

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JS2-WeM-OR.2 WEAR RESISTANCE OF TITANIUM-ALUMI-NIUM-CHRO-MIUM-NITRIDE NANOCOMPOSITE THIN FILMS. A. Alberdi, M. Marín, B. Díaz. Fundación Tekniker. Avda. Otaola, 20. 20600 Eibar (Spain). O. Sánchez. Institute of Materials Science (ICMM). Cantoblanco, 28049 Madrid (Spain) Titanium nitride, titanium-aluminium nitride and chromium nitride are now used widely in manufacturing industry to protect cutting and forming tools against wear. TiN was the first PVD ceramic coating to be used successfully to machine steel in industry and it is still the most recognized. TiN is a wear resistant coating suitable for a wide range of applications. It is used for machining carbon stainless steels, cast irons and aluminium alloys, protecting dies, moulds and a range of metal stamping and forming tools. However, TiN has now been superseded in many applications by TiAlN, which offers superior performance for a range of metal machin-ing and fabrication applications. It has been pointed out that the reason for this better perform-ance is the formation of aluminium oxide on the surface, which increases its operational tem-perature range. Although CrN is softer than TiN, CrN is a tough ceramic coating with good oxidation resistance. Presently, CrN is the PVD hard coating recommended for most metal forming applications. Advanced PVD coatings based on TiAlN are being developed recently, which possess en-hanced high temperature oxidation and wear resistance. Typical strategy to enlarge the tem-perature range of TiAlN is the addition of metals able to generate high resistant oxides, like chromium, molybdenum, yttrium or vanadium. In this way, authors have developed novel TiAlCrN multilayered nanocomposite thin films, which alternate CrN and TiAlN individual 10-12 nm thickness layers up to a total thickness of 1-3 μm. These coatings were grown on WC-Co inserts and high speed steel samples by simul-taneous arc evaporation of pure Cr and Ti-Al alloy targets. Wear resistance of these coatings was studied through high temperature pin-on-disk experiments. Results demonstrated that this kind of coating structures improved several times the wear resistance at high temperature of commercially available TiAlN coatings. Key words: TiAlCrN ceramic coatings, physical vapour deposition, high temperature wear re-sistance.

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JS2-WeM-OR.1 TRIBOLOGICAL PROPERTIES OF SILICON NITRIDE CERAMICS COATED WITH DLC AND DLC-Si AGAINST 316L STAINLESS STEEL J. R. Gomes. De-partamento de Engenharia Mecânica, CIICS, Universidade do Minho, 4800-058 Guimarães, Portu-gal. J. M. Carrapichano. Departamento de Engenharia Mecânica, Instituto Superior de Engenharia de Coimbra, 3040-228 Coimbra, Portugal. S. S. Camargo Jr., R. A. Simão, C. A. Achete. Departamento de Engenharia Metalúrgica e de Materiais, Universidade Federal do Rio de Janeiro, Cx. Postal 68505, 21945-970 Rio de Janeiro, RJ, Brazil. R. F. Silva. Departamento de Engenharia Cerâmica e do Vidro, CICECO, Universidade de Aveiro, 3810-193 Aveiro, Portugal. Diamond-like carbon (DLC) is an adequate coating on a large variety of materials for tribological purposes. Its intrinsic hardness, smoothness and solid lubricious capability are key properties that af-ford an outstanding combination of low friction coefficient and high wear resistance. However, the performance of a tribosystem is also determined by the type of counterface material, the environ-mental conditions and the presence or not of interfacial media. For example, in the automotive parts industry, the valve guides or the transmission gears are today coated with DLC. Another practical example of contacts that may involve steel as the mating material of DLC are forming tools to manu-facture steel products. Plasma enhanced chemical vapour deposition (PECVD) of DLC-Si or pure DLC coatings were performed, respectively, by conventional rf glow discharge from gaseous mix-tures of methane and silane or taking only pure methane. In this work, an engineering ceramic, sili-con nitride (Si3N4), is used as DLC substrate aiming the minimization of adhesion problems, usually found when some metallic substrates are employed. The ceramic substrates were placed onto the cathode of the deposition system where the rf power was applied achieving self-bias voltages vary-ing from -200 to -800 V. The tribological properties were assessed by pin (316L stainless steel)-on-disc (Si3N4) experiments, without lubricant, at room temperature, under ambient air and 50-60% relative humidity. The normal applied load assumed the values of 10 N and 20 N. The sliding speeds varied from 0.2 m/s to 1.0 m/s. The characterisation of the disc and pin worn surfaces was carried out by scanning electron mi-croscopy provided with energy dispersive X-ray spectrometry (SEM/EDS) and atomic force micros-copy (AFM). A first set of experiments was carried out in order to compare the tribological behav-iour of DLC-Si and pure DLC coatings on Si3N4. An early partial delamination of the DLC-Si coat-ings was observed, although leading to a steady-state friction regime with friction coefficients around 0.14, a low value in unlubricated conditions. This favourable frictional response is due to the wear-induced surface graphitisation and to the role of self-lubricating layers of adhered debris in both the sliding surfaces. The stainless steel contact surface was extensively covered by a Si, C and O rich tribolayer, promoting a third-body protection to the steel pin. An improved tribological re-sponse was obtained with pure DLC coated Si3N4 discs sliding against the stainless steel pins. This system almost instantaneously attains the steady-state friction regime, keeping the DLC film integ-rity, contrarily to the DLC-Si damaging, which leads to noisy friction curves coming from cyclic frictional events. The preservation of the coating demonstrates an adequate adhesion for tribological purposes up to 20 N of applied load. The wear coefficient of the pure DLC coated Si3N4 disc was, at least, one order of magnitude lower than that of the DLC-Si coated one, always below 10-6 mm3N-

1m-1. The set of tribological experiments of pure DLC coatings obtained under distinct self-bias ap-plication during the PECVD process revealed that the wear coefficient values obtained for the –200V biased coating are slightly better than those presented by the –800V biased one. However, with re-spect to the friction coefficient values, a trend to lower values occurs for the –800V biased films. Additionally, the typical friction pattern for low biased grown coating is much more unstable than the very smooth one of the –800V biased film.

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JS2-WeM-INV.1 SURFACE ANALYSIS OF NITRIDES AND OXYNITRIDE COM-POUNDS WITH ION BEAMS. E. Alves, N. P. Barradas, Instituto Tecnológico Nuclear, EN. 10, 2686-953 Sacavém .F. Vaz, L. Rebouta, C. Tavares, Universidade do Minho, Departamento de Física, 4800-058 Guimarães, Portugal. U. Kreissig, Forschungszentrum Rossendorf e.V., Postfach 510119, 01314 Dresden, Germany. Titanium nitride and oxynitride compounds exhibit interesting properties for applications in fields ranging from protective/decorative coatings to solar panels. The properties of these compounds are related to the oxide/nitride ratio and can be tailored by tuning this ratio. Then, accurate composition measurements are fundamental to understand the behaviour of these structures. Ion beam based tech-niques (IBA) are unique for this purpose. The composition throughout the entire thickness of the films was determined by Rutherford Backscatering Spectrometry (RBS). To get information on the profile of light elements (O, N) and detect the presence of hydrogen on the films, heavy ion elastic recoil detection analysis (HI-ERDA) was performed. The results indicate a nearly constant stoichiometry through the entire analysed depth. The oxygen fraction in the films increases with gas flow, reaching a value of x~0.33 for a reactive gas flow mix-ture of 6.25 sccm The colouration varied from the shiny golden for low oxygen contents (characteris-tic of TiN films) to dark blue for higher oxygen contents. During growth mixed zirconium nitride and oxide phases form. Furthermore, the deposition rate correlates with the oxygen content varia-tions, showing a continuous decrease with reactive gas flow.

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RIVA-SS-WEM-OR.8 THE TRIBOLOGICAL BEHAVIOUR OF W-S-C FILMS IN PIN-ON-DISK TESTING AT ELEVATED TEMPERATURE. M. Evaristo, T. Polcar, A. Cavaleiro, ICEMS -Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Dep. Eng. Mecânica, Rua Luís Reis Santos, 3030-788 Coimbra, Portugal Transition metal dichalcogenides (TMD) are well known for their self lubricant properties, due to unique crystal structure. However, the structure of TMD presents some drawbacks, particularly, they have low hardness making them inappropriate to applications requiring high load bearing capacity. Moreover, TMD films exhibit morphologies with high porosity promoting oxidation, particularly in humid atmosphere or elevated temperature. Several approaches have been used to increase the mechanical properties of TMD thin films. One of the most successful is either doping TMD with a metal, which increases hardness, or the deposition of an interlayer improving adhesion. MoS2 is one of the most studied TMD, showing good results when deposited with an interlayer and doped with Ti, Cr, and other metals. There is a reference in literature showing that WS2 has higher oxidation resistance than MoS2 (about 100ºC), therefore, it is a good candidate for films with good tribological behaviour at high tempera-tures. Previous works showed that the hardness and adhesion of W-S films doped with C or N depos-ited with a Ti interlayer significantly increased compared to pure WS2. The analysis of friction and wear behaviour at elevated temperatures was the main aim of this study. W-S-C films were deposited by magnetron sputtering in an Ar atmosphere with a Ti interlayer. A carbon target with several pellets of WS2 incrusted in the zone of the preferential erosion was used. The number of pellets was changed to modify the carbon content in the films, which varied from 26 up to 70at.%. Doping W-S films with carbon lead to a substantial increase of the hardness in the range 4 to 10GPa; the maximum of hardness was obtained for coatings with the carbon content of 40at.%. The XRD diffraction patterns showed that there was a loss of crystallinity with the increase of the carbon content in the film. SEM images of the cross section of the films showed decrease of the di-mensions of the columnar structure and decrease of the porosity as the carbon content in the films in-creased. The coatings were tested by pin-on-disk from room temperature (RT) up to 400ºC. At RT, the fric-tion coefficient was in range 0.3-0.1, and the wear rate decreased with the carbon content. At tem-peratures higher than 100ºC, the friction is below 0.1 for all compositions, which can be explained by the atmosphere drying. The tribological behaviour of the coatings with increasing temperatures depends on the films carbon content. For low carbon content up to 40at.%, the wear rate was almost independent of the tempera-ture up to 300º, while it increased dramatically in case of coatings with high carbon content. The highest carbon content (∼70at.%) coatings were peeled off from the substrate at temperatures ex-ceeding 100 ºC. In general, the limiting temperature for W-S-C coatings is 400ºC.

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RIVA-SS-WEM-OR.7 AB INITIO CALCULATIONS FOR THE EXCITED STATE AND THE CATION OF DIPHENYL ETHER AND COMPARISON WITH REMPI EXPERI-MENTS. M. Guerra and A. C. S. Paiva. CEFITEC Department of Physics, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.

The structure and minimum energy conformations of diphenyl ether (Ph2O) both for the ground state and the first excited state are calculated using HF/6-311++G**, MP2/6-311++G**, BLYP/6-311++G** and B3LYP/6-311++G** ab initio and density functional computations. Potential energy surfaces are also obtained for the rotation of the phenyl rings relatively to the C-O-C plane both for the neutral molecule and the positive ion. The global minimum of the Ph2O potential energy surface was found to be a “twisted” conformation and it doesn’t change with the excitation to the first ex-cited state nor with a single ionization, altough the C-O-C-C dihedral angle varies slightly and the molecule floppyness decreases. An initial study of the molecule fragmentation was performed at B3LYP/6-311++G** theory level. The spectra of Ph2O cooled in a supersonic jet expansion, obtained with one-color resonance en-hanced two-photon ionization suggests the existence of different conformations[1]. The first excited state low-frequency vibrations for three of the conformers were investigated using a Configuration Interaction aproach (CI-Singles) and Complete Active Space Multiconfiguration Self Consistent Field (CASSCF) method. The comparison between the calculated and observed spectra for all the conformers thus allows us to assign the major bands. Keywords: Conformational analysis; Diphenyl ether; Photoionization; Ab initio calculation [1] A. C. S. Paiva et al., International Journal of Mass Spectrometry 221 (2002) 107-115

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RIVA-SS-WeM-OR.6 SURFACE ANALYSIS OF NBR ELASTOMERS MODIFIED WITH DIFFERENT PLASMA TREATMENTS. L. Martínez, L. Álvarez, Y. Huttel, J. Méndez, E. Román. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) Cantoblanco, 28049-Madrid, Spain. A. Vanhulsel, B. Verheyde, R. Jacobs, Flemish Institute for Technological Research (VITO). Boeretang 200, 2400-MOL, Belgium.

In this work, three rubber–like materials with applications applied in the automotive industry were studied: two Nitrile Butyl Rubber (NBR 7201 and NBR 9003) and one Hydrogenated Nitrile Butyl Rubber (HNBR 8001). Different atmospheric pressure plasma treatments were used to modify the surface properties of these materials in order to improve their tribological (properties). Surface analysis of the samples by means of X-ray Photoelectron Spectroscopy (XPS) was performed in or-der to get information about the surface chemistry and the elemental composition of the contact sur-faces. In addition, wetting experiments were also performed by measuring the contact angle with in the frame of the sessile drop method. The obtained results allow an evaluation of the surface free en-ergy of the solids and of the impact of different plasma treatments. The XPS results showed a modi-fication of the surface composition of both NBR rubbers, while the same treatments produced slight modifications on the surface chemistry of the HNBR. The main modification was based on an in-crease in the oxygen content. The combination of N2 and CH3COOH produced the strongest modifi-cations of the surface composition of the tested elastomers. All these surface modifications also pro-duced a change on the surface energy of the rubber-like materials. The results obtained in the contact angle measurements revealed that the plasma treatments produced a modification of the wettability of the rubber-like NBRs and, therefore, a modification of their surface free energy.

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RIVA-SS-WeM-OR.5 DEVELOPMENT OF AN APPLICATION FOR MONI-TORIZATION AND ANALYSIS OF THE ELECTRIC SIGNAL OF AN ULTRAVIOLET PHOTOELECTRON SPECTROMETER. P. M. S. Cristo, A. A. Dias, P. Vieira, M. L. Costa. 1Centre for Physics and Technological Research, CEFITEC, 2Departamento Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, 2829-516, Caparica, Por-tugal. e-mail: [email protected] The development of an application for monitorization and analysis of the electric signal of an ultra-violet photoelectron spectrometer [i], witch allows for more precision in both the spectrometer analysis parameters and in the collected data, is presented. The principal features are the control of the voltage applied to the analyser hemispheres and the ac-quisition of counts from the spectrometer. A Labview programming environment was chosen, jointly with a Data Acquisition board for the counting, input and output data. The construction of a Digital-Analogic converter is also included in the project in order to convert the digital signal available in the acquisition board and controlled by the Labview to analogical data for input in the spectrometer. References [i] F. Innocenti, L. Zuin, M.L. Costa, A.A. Dias, A. Morris, A.C.S. Paiva, S. Stranges, J.B. West, J.M. Dyke, J. Elec. Spec. Rel. Phen. 2005, 142, 241-252.

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RIVA-SS-WeM-OR.4 DESIGN OF AN ELECTROSTATIC LENS SYSTEM FOR AN ULTRAVIOLET PHOTOELECTRON SPECTROMETER. R. M. Pinto1,2, A. A. Dias1,2 and M. L. Costa1,2. 1Centre for Physics and Technological Research, CEFITEC, 2Departamento Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, 2829-516, Caparica, Portugal e-mail: [email protected] The control of an electron beam plays an important role in most of the electron spectrometer sys-tems, nowadays. Although the use of electrostatic lenses, for purposes of focusing the particles, is not always necessary, the overall quality of the system in which they are inserted can be improved. This work aims to design an electrostatic lens system [i] that improves the resolution at the entrance of a hemispherical deflection analyzer, of a working ultraviolet photoelectron spectrometer [ii,iii], while maintaining a constant transmission. The spectrometer does not have any kind of controlled focusing device other than a spatial collima-tor. An optimal solution has to be found, concerning the dimensions of the existing apparatus. Simu-lations using ion optics programs and the study of several lenses configurations are the suitable means to reach such a goal. The existence of aberrations is taken into account. References [i] O. Sise, M. Ulu, M. Dogan. Nucl. Instr. and Meth. in Phys. Res. A 2005, 554, 114-131. [ii] J.M. Dyke, G. Levita, A. Morris, J.S. Ogden, A.A. Dias, M. Algarra, J.P. Santos, M.L. Cos-ta, P. Rodrigues, M. Andrade, M.T. Barros. Chem. Eur. J. 2005, 11, 1665-1676. [iii] L. Beeching, A.A. Dias, J.M. Dyke, A. Morris, S. Stranges, J. West, N. Zema, L. Zuin, Molecu-lar Physics 2003, 101, 575-582.

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RIVA-SS-WeM-OR.3 WORK FUNCTION CHANGES INDUCED BY TEMPERATURE IN Ag/TiO2 SURFACES. H. P. Marques, A. R. Canário, A. M. C. Moutinho and O. M. N. D. Teodoro CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 CAPARICA, Portugal When one studies the catalytic behaviour of a surface, the energy required to remove electrons from the surface is a meaningful parameter since electron transfer is involved in many surface reactions. Therefore, the surface work function is important to understand the mechanisms of heterogeneous catalysis. Growth dynamics of silver clusters supported on TiO2 (110) mono-crystals have been studied by several authors [1-5]. Silver atoms deposited in the crystal at room temperature exhibit a 3D Volmer-Weber growth mode. When the substrate is cooled to LN2 temperature, the Ag atoms have very low surface mobility and a quasi-2D growth is observed [2]. The work function measurements performed during cluster growth show different behaviour depend-ing on the substrate temperature, which translates on the cluster size [6]. During growth, at lower temperature the WF changes more rapidly and tends to a lower value than at room temperature. In this work we studied the work function as a function of the substrate temperature. One equivalent monolayer of silver was deposited on a TiO2 (110) surface at LN2 temperature and a base value for the work function was determined. The substrate was then annealed for 5 minutes. The sample was allowed to cool down again to LN2 temperature and the work function was measured. The procedure was repeated for increasing annealing temperatures up to 200ºC. For all work function measurements the onset method was used. The secondary electron threshold is shifted in energy according to the work function change. Keywords: Work function, titanium oxide, silver clusters.

[1] U. Diebold, Surface Science Reports, 48 (2003) 53. [2] C.T. Campbell, Surf. Sc. Reports, 27(1997) 1 111 [3] C. Su, J.C. Yeh, J.L. Lin and J.-C. Lin, App. Surf. Sci. 169 (2001) 366. [4] K. Luo, T.P. St Clair, X. Lai, and D.W. Goodman, J. of Phys. Chem. B 104 (2000) 3050. [5] A.R. Canário, E.A. Sanchez, Yu. Bandurin and V.A. Esaulov, Surf. Sci. 547 (2003) L887 [6] H.P. Marques, A.R. Canário, O.M.N.D. Teodoro and A.M.C. Moutinho Riva V

proceedings, submitted to Vacuum

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RIVA-SS-WeM-OR.2 PLANAR MAGNETRON DISCHARGE. AN EXPERIMENTAL PROFILE ANALYSIS OF THE TARGET EROSION BASED ON A TWO-DIMENSIONAL FLUID MODEL IN THE STEADY STATE. M. L. Escrivão, P. J. S. Pereira*, M. R. Teixeira and M. J. P. Maneira. CeFITec, Departa-mento de Física, Faculdade de Ciências e Tec-nologia da Universidade Nova de Lisboa, Quin-ta da Torre, 2829-516, Caparica, Portugal. * Also in Área Científica da Matemática, Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro, 1949-014 Lisboa, Portugal . In the present work the erosion depth is measured along a diameter of a circular magnetron target. The horizontal and vertical components of the magnetic induction are measured at points of the plasma that are vertically above this diameter and at different distances from the target. The experimental profile of the target erosion is analysed on the basis of the plasma density distribu-tion near the target which is obtained using a two-dimensional fluid model in the steady state.

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RIVA-SS-WeM-OR.1 USE OF A RADIO-FREQUENCY POWER SUPPLY COUPLED TO A HIGH TEMPERATURE FURNACE IN ULTRAVIOLET PHOTOELECTRON SPEC-TROSCOPY. E. M. C. C. Reis1,2, A. A. Dias1,2, O. M. N. D. Teodoro1,2 and M. L. Costa1,2. 1Centre for Physics and Technological Research, CEFITEC. 2Departamento Física Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Monte de Caparica, 2829-516, Caparica, Portugal. e-mail: [email protected] Temperatures up to 2500 ºC have to be attained for analysing solid samples by Ultraviolet Photoelec-tron Spectroscopy (UVPES), using a high temperature furnace[i]. A radio-frequency (RF) power supply seems ideal for this purpose [ii]. The RF source, operating near the photoelectron spectrometer, creates an electromagnetic field that causes interference in photoelectron trajectories. In order to eliminate this effect the RF power sup-ply should be used in a pulsed mode in conjunction with a linear gate in detector circuits. The frequency chosen to obtain these pulses is of 50 Hz, since that is the frequency used by the mains. The 50 Hz waves are rectified, being allowed to pass only the positive voltages, eliminating the negative ones. Considering that the maximum power available from the generator is reduced to less than half of its original value, as a result of the pulses, a considerable amount of power is necessary to raise the temperature. Modifications performed in both a RF power supply and detector circuits, together with its coupling to an existing high temperature furnace will be presented. References [i] J.M. Dyke, G. Levita, A. Morris, J. S. Ogden, A.A. Dias, M. Algarra, J.P. Santos, M.L. Costa, M.T. Barros, J. Phys. Chem. A 2004, 108, 5299-5307. [ii] D. Bulgin, J. Dyke, F. Goodfellow, N. Jonathan, E. Lee, A. Morris, J. Elec. Spec. Rel. Phen. 1977, 12, 67-76. “

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RIVA-SS-WeM-INV.1 STM STUDY OF MODIFICATIONS ON VACUUM FIRED 304L STAINLESS STEEL SURFACES. M. Leisch and A. Stupnik. Institute for Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria In UHV and XHV applications high temperature bakeout (vacuum firing) is a common method to re-duce the hydrogen outgassing rate from stainless steel surfaces. This procedure reduces the amount of hydrogen in the bulk. At low bulk concentration hydrogen, outgassing is basically limited by sur-face recombination. The surface of glass bead blasted 304L steel samples was investigated by STM after normal bakeout procedure at 300°C and after vacuum firing at 1000°C. During vacuum firing a complete reconstruc-tion of the surface can be observed. Already after 5 min of vacuum firing the formation of (111) ter-races with monoatomic steps can be found. Slightly tilted crystallites exhibit (111) terraces inter-sected by bunched steps and facets. These facets form a nearly regularly pattern corresponding in orientation almost to the (100) and (110) planes. After 15 min vacuum firing large (111) terraces with extensions up to 200nm intersected by bunched steps can be observed. The general appearance of the surface after vacuum firing indicates a significant reduction of active sites for recombination of hydrogen. This supports the present understanding of outgassing for this material. Supported by „Zukunftsfonds des Landes Steiermark“

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WeM-Pl.3 FUNCTIONAL CERAMIC THIN FILMS, NEW MATERIALS FOR THE FUTURE, FROM NATURALLY NANOLAMINATED MAX-PHASES TO TAILORED NANOCOMPOSITES OF CARBIDES, OXIDES AND NITRIDES. H. Högberg, Thin Film Physics Division, Department of Physics (IFM), Linköping University, SE-58183 Linköping, Swe-den. There is a strong desire to design a material with properties that match the demands foreseen in fu-ture applications. Thus, the development of functional materials is gaining increased attention in ma-terials science today. This presentation focuses on two such highly promising branches of functional thin films, namely the layered ternary ceramic compounds known as the Mn+1AXn (n=1-3) phases, where M is an early transition metal (Ti, Nb), A is a group 13-15 element (Al, Si, Ge), and (X) is ei-ther C or N, and nanocomposites from the TiC/SiC, TiN/SiNx and ZrO2/Al2O3 systems. A limited miscibility for one of the constituents is inherent to all of these systems, which causes segregation of the element during synthesis. For the MAX phases, typically synthesized as bulk materials at tem-peratures of ∼1300 oC, the process yields an anisotropic crystal structure in which MX blocks are in-terleaved by pure A-element layers. This nanolaminated structure give rise to the unique set of prop-erties for these materials as reported by Barsoum et al. Typically the MAX phases show high oxida-tion resistance in combination with good thermal and electrical conductivities. These attributes are also ideal for advanced thin film applications were multi-functionality is required at elevated tem-peratures and/or harsh environment. Recently, we have developed dc magnetron sputtering processes for the growth of MAX-phase thin films from the systems Ti-A-C, A=Al, Si, Ge, or Sn, using either growth from elemental sources or Ti3SiC2 and Ti2AlC (MAXTHAL®) targets. The processes en-ables the growth of epitaxial thin films on Al2O3(0001) substrates at substrate temperatures in the re-gion 700-1000 oC, including known bulk phases such as Ti2GeC, Ti2SnC, Ti3SiC2, and Ti3GeC2 as well as new phases Ti4SiC3, Ti4GeC3, and Ti3SnC2. Characterization with four-point probe resistivity measurements shows that our thin films are good conductors. Nanoindentation confirms the ductile deformation behavior of the MAX phases and reveals details on the formation of pile up. For the nanocomposite thin films from particularly the TiN/SiNx system the pioneering work by Vepřek et al has provided invaluable knowledge regarding the microstructure design of films with improved properties. Their studies show that increased hardness is only achieved when the secon-dary amorphous phase (SiNx) form a 1-2 monolayer thick tissue around small (<10 nm) and subse-quently dislocation free grains of TiN. This concept for design seems to be applicable also to other systems such as TiC/SiC and ZrO2/Al2O3, thereby allowing other technologically important proper-ties to be improved as well. We recently demonstrated that TiC/SiC thin films grown by magnetron sputtering from a single Ti3SiC2 (MAXTHAL®) target at 300 oC exhibit electrical contact properties similar to those of the noble metals, but combined with a better mechanical response. For RF magne-tron sputtered ZrO2/Al2O3 films deposited from compound sources at temperatures of 450 oC we found evidence that the metastable cubic ZrO2 phase is stabilized in an XRD amorphous matrix of alumina. This is a promising route to yield better fracture resistant materials due to the more favor-able crack absorption properties shown by the cubic phase compared to the tetragonal phase. New and valuable insights on how the interfaces in nanocomposite thin films are organized have also been found recently. Studies preformed on the TiN/SiNx system at Linköping show that the secondary phase (SiNx) is not entirely amorphous, since a lattice matched growth of the crystalline metastable cubic (SiNx) was discovered on the surfaces of the TiN crystallites. These findings are likely to have impact on the future development of nanocomposite thin films not only from the studied system, but also for other systems, such as TiC/a-SiC and ZrO2/Al2O3.

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WS-18-TuA-INV.8 ADVANCED PROCESS AND EQUIPMENT CONTROL (APC/AEC) THROUGH FINE GAS ANALYSIS IN VACUUM SYSTEMS FOR SEMICONDUCTOR MANUFACTURING. Giuseppe FAZIO, ST Microelectronics - Italy In the Advanced Process and Equipment Control (APC/AEC) the studies and the evaluations related to new methodologies and new devices are considered key activities. In vacuum chamber the Optical Emission Spectroscopy (OES) and Residual Gas Analyzer (RGA) are two instruments consolidated and widely utilized due to their high performance and flexibility.

OES and RGA applications Main application Other application OES Process Control

(i.e., End Point Detection) Equipment Control (i.e., finger print equipment)

RGA Equipment Control (i.e., leak detection)

Process Control (i.e., degas step optimization)

Also from APC/AEC point of view these two instruments (OES and RGA) and their various applica-ble methodologies (process and equipment control) have to be continuously developed. Some of our direct experiences concerning these aspects will be showed. OES example Optical emission spectroscopy (OES) is widely used to perform in situ characterization and plasma processing control, as for instance in dry etching end point detection. In current practice only UV-VIS range is used, which corresponds to electronic transitions of mo-lecular or atomic levels. However, when areas to be patterned within the wafer are small, and etching selectivity is not well known, the OES could not be enough. To detect the optical end point a new portion of the spectra has been studied (corresponding to mo-lecular vibrational modes) and its emission enhancement. RGA example When the pressure is lower than 10mTorr a miniature array of quadrupole mass spectrometers has been considered (Micropole™ sensor). This sensor has a small size and it is feasible to install it in a small volume, without loosing high per-formances, and turns out to be very flexible on applications. Recently an instrument for advanced diagnostic using the RGA Micropole™ has been developed. This instrument allows technicians to control the vacuum chambers in order to have higher accuracy and faster analysis, requirements more and more important for hi-tech industries like the semicon-ductor one. When the pressure is higher than 10mTorr the traditional RGA (quadrupole) requires pump system. For this reason the system is not suitable for industrial field: cumbersome and complicated from a maintenance point of view. Therefore, we have evaluated alternative instruments: ICP plasma source, analysis by OES of atomic and molecular emission due to plasma excitation of residual gases. Hardware malfunctions were simulated on etch equipment and the consequent behaviour of the plasma emission spectrum was analyzed in order to evaluate and quantify detectable differences. The installation of this type of sensor on Transfer Module of the metal etch tool has been planned for the detection in line for leakage and humidity. In particular the focus concerns the wet cleaning re-covery after PM and the reduction of the possible particle contamination produced by humidity.

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WS-18-TuA-INV.7 THE DESIGN AND OPERATION OF THE JET VAC-UUM AND FUELLING SYSTEMS AND THEIR RELEVANCE TO ITER. R J H Pearce, Euratom-UKAEA Association, Culham Science Centre, Oxon, OX14 3DB. UK . M. Wykes, ITER IT, IPP, Boltzmannstr. 2, 85748 Garching, Germany. JET is the world largest magnetic confinement fusion device and the only device with the capability to operate with tritium. JET first operated in 1983 and since this time it has been regularly enhanced and upgraded. Agreement is now well advanced for building ITER at Caderache in France. JET has played a key role in the ITER design, in particular by operating in deuterium/tritium, by testing di-vertor designs, in developing first wall technology, by operating with high power heating systems and in consolidating ITER operating scenarios. The JET main vacuum vessel is of doubled walled construction of volume ~200m3 and is capable of being baked to 320o C. It is pumped by turbo-molecular pumps in addition to a high pumping speed cryogenic pump in the divertor region. Typically JET now operates at 200o C with a base pressure in the 10-8 mbar region. The total pressure is dominated by deuterium outgassing and by the vapour pressure of deuterium held on the supper critical helium cryogenic pumps. Impurity partial pressures are in the 10-10 mbar region. The JET vacuum vessel and other vacuum containment system also act as the primary containment system for tritium injected or stored in the JET. This necessitates the need for high integrity on all boundary components and double containment on delicate components. The vacuum characteristic of JET are significantly affected by plasma facing components. These have been an important area of development and change in magnetic confinement fusion devices. On JET the vacuum vessel’s first wall has been regularly changed, progressing from inconel, to graph-ite, to the current carbon fibre composite (CFC). In addition various experiments with partial beryl-lium coverage have been performed. A full beryllium wall with a tungsten coated, CFC divertor is planned for the future as a reference for ITER. The physics programme on JET has lead to demanding requirements for the supply of gas to the to-rus. In particular the pumped divertor necessitates scenarios with high fuelling rates. In total 12 fuel-ling points are used. It is required to deal with large numbers of gas species, expensive gas species, reactive gas species as well as tritium gas. An automated system is used for introducing gas into JET. The system gives the flexibility for gases to be changed frequently without compromising gas purity. Three successful experimental tritium campaigns have been performed on JET. An initial tritium in-ventory of 20g has been used for a total injection, to date, of ~36g. The experiments have provided very valuable experience in complex systems on, tritium handling, retention and accounting. New challenges will however be encountered within the ITER fuel cycle with ~3Kg of tritium proposed to be on site and ~850Kg to be injected through the life of ITER. The design and operation main JET vacuum and fuelling systems are described. These are compared with the proposed systems for ITER. Where there is particular ITER relevant experience, in the de-sign, manufacturing, and operation of vacuum and fuelling systems, this is highlighted.

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WS-18-TuA-INV.6 QUALITY CONTROL AND LEAK DETECTION IN LARGE VAC-UUM SYSTEMS. P. Chiggiato. CERN, European Organization for Nuclear Research. CH-1211 Geneva 23, Switzerland. Large ultra-high vacuum systems can be jeopardized by the failure of a single vacuum component. As a consequence, a careful choice of materials, assembling techniques and surface treatments is mandatory in order to avoid leaks (both real and virtual) and excessive outgassing that could spoil the efficiency of the pumping system. However, even if the suitable choice of the production proce-dure is taken, a dedicated quality control plan is essential to avoid the result of clumsy operations and drifts in the production parameters. For the Large Hadron Collider (LHC), which is under construction at CERN and expected to run at the end of 2007, thousands of vacuum components are being produced and different quality control programs are applied. For the particular case of the about 1200 long straight section (LSS) vacuum chambers, the quality insurance program will be reviewed by taking into account the most critical steps of the production procedure, namely extrusion of the OFS tubes, vacuum brazing of the flanges, TIG welding, chemical treatment of the inner surface, and deposition of the Ti-Zr-V non-evaporable getter (NEG) thin film. Several characterization techniques are involved, for example X-ray radiography, optical and metallurgical analysis, leak detection, surface sensitive inspection (XPS and AES) and non-traditional vacuum measurements. The quality control plan continues also after the installation of the components in the accelerator ring or into complex devices like superconducting magnets and distributing field boxes. In this context, the validation criteria for the NEG film activation process in the LSS will be presented. In addition, an alternative method for detecting leaks in the complex cryogenic lines of the superconductive quadrupoles of the LHC will be described. In order to save and to simply retrieve the massive quantity of data coming from the different con-trols, a dedicated software has bee developed at CERN; for most of the components installed in the main ring, it allows the tracking of all the production and control reports together with the actual po-sition in the accelerator.

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ROUND TABLE CHAIRMAN: J. M. ALBELLA ICMM-CSIC-ES PRESENTERS: A. CAVALEIRO UNIVERSITY OF COIMBRA. PT J.A. GARCÍA AIN, ES F, ORGAZ MEC.ES

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JS1-TuM-INV.12 MICROFABRICATION BY DIRECT WRITING ON DIELECTRICSUSING ULTRASHORT LASER PULSES. J. Solis, Instituto de Optica, CSIC, Serrano 121, E-28006 Madrid, SPAIN

Subsurface modification of transparent materials with femtosecond laser pulses is a promising toolfor the fabrication of 3-D photonic elements. However, in spite of its successful application to theproduction of waveguides and other photonic elements such as gratings, waveguide amplifiers, orphotonic band-gap structures in a variety of dielectric materials, its widespread use is still hamperedby several problems related to the control of energy deposition inside the dielectric material. Thepresence of spherical aberrations, as a consequence of the refractive index mismatch at the air-dielectric interface, as well as non-linear propagation phenomena have already been identified ascritical issues, very particularly in high refractive index materials. The presentation will provide anoverview of the fundamentals of this processing technique as well as different strategies aimed eitherat better controlling the energy deposition inside the material or at producing functional photonicelements in “difficult” materials like heavy metal oxide glasses.

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JS1-TuA-INV.11 SURFACE FUNCTIONALIZATION OF CERAMIC TILES BY NOVEL DESIGN TECHNIQUES (PLASMA, INK JET, ETC.) J. Ribera, Invest Plasma S.L. Poligono Estadio, Nave 34. 12004 Castellon. J. Carda, Inorganic and Organic Chemistry dept, Cam-pus Riu Sec, Universitat Jaume I. 12080 Castellón Spanish ceramic industry is one of the major world producers of ceramic tiles reaching annual pro-duction volume of more than 600 million m2. Nevertheless currently high competition by other coun-tries can be observed. This makes necessary to introduce higher added value to the products, creating new functionalities. One of the important areas of interest in near future is surface treatment with the use of nanoparticles and thin-film technology and new processes in order to obtain functionally new products with higher added value. In this respect a review of the traditional decorative techniques for ceramic tiles, indicating the new possibilities of plasma-coating of metal and oxide coatings and laser treatment with decorative purposes in order to create desired colour in situ. As well the ink jet tech-nologies and development of new nanoparticulate pigments development in the will be highlighted.

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JS1-TuA-INV.10 DECORATIVE COATINGS ON ENAMEL CERAMICS DEPOS-ITED BY PVD TECHNIQUES. A. Alberdi. Fundación Tekniker. Avda. Otaola, 20. 20600 Eibar, Spain..F. Lucas, A. Belda. Fritta S.L. CV-20 Km 8, 12200 Onda (Castellón), Spain.Mª José Orts. Instituto de Tecnología Cerámica (ITC). Campus Universitario Riu Sec, 12006 Cas-tellón, Spain Ceramic tiles - floor tiles, wall tiles and other decorative articles - are usually made by firing a ce-ramic backing, which is coated with a consolidated layer of frits and crystalline materials that glaze after the baking process. The ceramic backing may be raw, as when the single-fire method is used, or else baked, when the double-fire method is used. Obviously, ceramic glazed products must have technical and decorative qualities that make them suitable for the use to which they are to be put, such as hardness, resistance to cracking, wear and scratching, imperviousness and insolubility in water and in those acids and alkalis with which they may enter into contact in normal use. Decorative effects are created depending on the finishing process used, for example, gloss or matt, opaque or transparent, smooth or granulated, polished, etc. Modern decorative trends ask for conferring the tile a metallic appearance. Current ceramic metallizing techniques normally consist of adding a given amount of metal to the baked tiles, but prior to glazing or final enamelling, so their finishes have very low scuff and scratching resistance, being impossible to use on floors or facades, and they are not resistant to chemical attack. Furthermore, the gloss of current finishes does not exceed 200‰ at angle of inci-dence of 60º. Recently, new metallizing techniques have been developed using Physical Vapour Deposition (PVD) methods. The authors set up a novel procedure to metallise enamelled products. Under vac-uum and after degassing the tile backing, a metallic coating grows on the enamelled tile surface by bombardment with metallic ions and neutral atoms of titanium, zirconium, tantalum or chromium. These atomic species are generated by a high intensity arc discharge (in the range 50-250 A) be-tween an electrode made of the metal of interest, normally a rod, pipe or plate, and an auxiliary coo-per electrode. Apart from pure metal films, nitrides and carbo-nitrides of these metals can be also deposited on the tile surface by adding nitrogen and hydro carbide gases in the vacuum chamber. Using this new procedure, enamelled tiles coated with 0.3 microns thick decorative films were pro-duced, which show attractive colours and metal appearance. Finishing colours depended on thechemical nature of the film: golden (zirconium, titanium and tantalum nitrides), metallic grey (chro-mium nitride, and pure Ti, Zr or Cr), reddish brown or purple (titanium carbo-nitrides). Apart fromthe attractive colour, these decorative surfaces exhibit an outstanding metallic gloss (ZrN 736‰ atangle of incidence of 60º), and excellent resistance to acids and alkaline substances.

Key words: Ceramic tiles, decorative coatings, physical vapour deposition. .

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JS1-TuA-INV.9 HARD DECORATIVE METAL-OXYNITRIDE THIN FILMS PRE-PARED BY PVD. F. Vaz, P. Carvalho.Departamento de Física, Universidade do Minho, 4800-058 Guimarães, Portugal. The main objective of this work is the preparation of decorative zirconium oxynitride, ZrOxNy, thin films by dc reactive magnetron sputtering. Film properties were analyzed as a function of the reac-tive gas flow and were correlated with the observed structural changes. Measurements showed a sys-tematic decrease in deposition rate with the increase of the reactive gas flow and revealed 3 distinct modes: i) metallic mode, ii) a transition mode and iii) an oxide mode. The measurements of target potential were also consistent with these changes, revealing a systematic increase from 314 to 337 V. Structural characterization uncovered different behaviors within each of the different zones, with a strong dependence of film texture on the oxygen content. These structural changes were also con-firmed by resistively measurements, whose values ranged from 250-400 ��cm for low gas flows and up to 106 ��cm for the highest flow rates. Color measurements in the films revealed a change from bright yellow at low reactive gas flows, to red-brownish at intermediate flows and dark blue for films prepared at the highest flows. Hardness measurements gave higher values for the region where larger grain sizes were found, showing that the grain growth hardening effect is one of the main pa-rameters that can help explain the observed behavior. Also the peak intensity ratio and the residual stress states were found to be important factors for explaining this behavior.

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JUNE 27 TUESDAY MORNING

WS-18-TuM-OR.10 A NEW PROCEDURE AND DEVICE FOR THE STUDY OF HY-DRIDING PROCESSES FROM THE INNER SURFACE OF NUCLEAR FUEL CLAD-DINGS. M. Díaza, J. S. Moyaa, J. L. Sacedóna* a Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, Madrid-28049, Spain. B. Remartínezb, S. Pérezb. bTEMAT Iberdrola, Pº Virgen del Puerto, Madrid-28005, Spain

A new method and UHV equipment 1,2 that allows the study of the hydriding process of fuel clad-dings from the inner surface is described. The hydriding is performed by heating the cladding in an ultra-high vacuum chamber while hydrogen flows inside the tube. The external H2 partial pressure, the tube electrical resistance and the power dissipated by the reaction are measured throughout the process. These measurements at different hydriding stages are complemented with an optical micros-copy analysis of the claddings give insight into the main physical processes 1. As a consequence a description of the hydriding first stages is provided. The method allows the measurement of the in-cubation and failure times and the total energy dissipated by the hydriding reaction. In addition, use-ful information about the kinetics of the hydriding process is obtained from external H2 partial pres-sure vs hydride rim thickness plot This method has been applied to test the durability and reliability against the hydriding reaction of commercial fuel claddings of zirconium alloys with different compositions and thermal treatments. An additional study of the variation of Vickers hardness and elastic modulus with the stoichiometry and thickness of the zirconium hydride rim formed inside this type of claddings has been carried out by nanoindentation and XRD measurements. From these results it is possible to obtain some conclu-sions about the mechanical stress distribution induced by the hydriding process and its influence in the failure of these industrial elements. 1 Patent No.: US 6,873,672 B2 1 Patent No.: WO 2005/076286 A1 1 J. L. Sacedón, M. Díaz, J. S. Moya, B. Remartínez, J. Izquierdo, Journal of Nuclear Materials, 327 (2004) 11-18.

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WS-18-TuM-OR.9 CALIBRATION OF HELIUM LEAKS: REFERENCE METHOD AND DISSEMINATION. RANGE FROM 4.10-14 MOLE.S-1 (10-10 PA.M3.S-1) TO 4.10-6 MOLE.S-1 (10-2 PA.M3.S-1). Pierre OTAL, Frédéric BOINEAU, Jean-Claude LEGRAS. Labora-toire National de Métrologie et d’Essais (LNE) LNE developed in the last years a new method for the calibration of helium leaks. It is based on the measurement of the pressure variation �p due to the flow rate of the leak in a known volume. The pressure is measured using a capacitance diaphragm gauge starting at about 3 Pa. A capillary leak is calibrated as a function of the input pressure for both helium and nitrogen. The pressure variation al-lows to creating a flow range over a decade.

Then the leak is supplied with mixtures of helium in nitrogen at different known concentrations down to 100 ppm. The flow rate of helium is calculated from the total flow measured by the �p and the concentration measured in the LNE gas analysis laboratory. Different combinations of input pressure and concentrations allow to defining step by step the flow scale down to 4.10-14 mole.s-1. An uncertainty budget will be presented. The estimated uncertainty is ranged from 2 % at 4.10-6 mole.s-1 to 5.5 % at 4.10-14 mole.s-1. Two methods are used for disseminating the measurements to industry:

- A method by substitution, where the helium leak so defined is used to reproduce the same output signal of a leak detector as observed with a working reference leak.

- A direct measurement of the client helium leak using the output signal of the leak detector. In that case, the output signal is fitted as a function of the leak over 3 decades using 5 helium leaks firstly calibrated.

Some results related to the linearity and the reproducibility of the leak detector will be given. A comparison with another calibration technique developed for the low gas flow measurement has been carried out in the higher part of the range. The agreement between the two methods operating under vacuum for the first one and near the atmosphere for the other one was about 1 %, inside the estimated combined uncertainty.

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WS-18-TuM-OR.8 CURRENT TRENDS IN LEAK TESTING TECHNOLOGY A. P. Fonseca, H. P. Marques, A. M. C. Moutinho and O. M. N. D. Teodoro. METROVAC – Labo-ratório de Tecnologia e Metrologia de Vácuo. CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 CAPARICA, Portugal Leak detection techniques are not of exclusive use of the vacuum scientist but are increasingly taking their place in the demanding industrial environment. Accordingly, the definition of what is a leak must also evolve to accommodate the points of view of the industry. A leak always involves a flow of mass though the walls of a vessel. It usually results in an escape of liquids, vacuum or gases from sealed components or systems. Due to the demands of the electronics industry and increased activities in space exploration, the need to develop new equipments and devices that had to be free of significant leakage appeared. The maximum acceptable leak rate for a given product depends upon the nature of the product. In a compact electronic device, like a photon multiplier, with a size of 2 cm3 even a leak rate of 10-

10 mbar l s-1 will be too high, producing a lifetime of only about 7 hours! Leak detectors range in complexity from a tank of water, in which bubbles from a leak can be seen, to highly sophisticated systems using radioactive tracer gases, depending on the leak detection tech-nique – e.g. acoustics, hydrostatic test, tracer fluids or gases, high voltage discharge. However, is the application that defines the most appropriated method. Commercial helium mass spectrometer leak detectors can commonly detect leaks down to 10-10 mbar.l.s-1 range. Lower rates can appear from molecular permeation and not from orifices and there-fore are difficult to distinguish. High sensitivity in commercial leak detectors is longer the most demanded requirement. Most devel-opments are being made in order to miniaturize the detectors as well as to fully automate its opera-tion. It has been developed a miniature mass spectrometer [ref MKS] with dimensions of 30x30x15 cm and weight less than 8 kg. With this kind of portable detectors it’s less time-consuming to detect leaks in large vacuum systems that often require access to a great number of test points. The latest published papers favour developments in acoustics detection technology for example Hol-land et al describes a method for in-orbit identification and location of a leak in the International Space Station using structure-borne ultra-sonic noise. In this paper is work we summarize the most suitable leak detection methods according to the appli-cation and the maximum admissible leak rate.

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WS-18-TuM-OR.7 HEALIUM LEAKS TRACEBILITY AT CZECH METROLOGY INSTITUTE (CMI). Dominik Prazak. Czech Metrology Institute, Okruzni 31, 638 00, Brno, Czech Republic. Jiri Tesar. Czech Metrology Institute, Okruzni 31, 638 00, Brno, Czech Republic. Petr Repa. Charles University Prague, V Holesovickach 2, 180 00, Prague 8, Czech Republic. Ladislav Peksa. Charles University Prague, V Holesovickach 2, 180 00, Prague 8, Czech Republic. Tomas Gronych. Charles University Prague, V Holesovickach 2, 180 00, Prague 8, Czech Republic. Martin Vicar. Czech Metrology Institute, Okruzni 31, 638 00, Brno, Czech Republic. The tightness of vacuum systems has very high and increasing importance in contemporary research, industry and safety of work. Its consequence is continuous and growing demand for the calibration services in this field. Mass spectrometers as helium leak detectors are traditionally used for accurate measurement of vac-uum leaks. The critical point of their accuracy is their low long-term stability. It is necessary to cali-brate them with very short recalibration periods utilizing the secondary helium leak standards. But, of course, these secondary standards need the traceability to the standards of higher order. Until re-cently, CMI has used the services of other national metrological laboratories, but this system has been becoming more and more insufficient. So there has been decided to build our own primary standard of vacuum leaks in the framework of United vacuum laboratory of CMI and Charles University – Prague. The recently finished high vac-uum standard based on continuous expansion has been chosen as the base leading to the reduction of costs. That implies use of constant pressure - variable volume flow meter and comparative measure-ment method. Its preliminary range is 3.10-7 - 7.10-4 Pa.m3.s-1 with uncertainty less than 0.5 %, but we study the possibilities of its extending. First of all it is needed in the lower range limit. The paper will describe the problems that have occurred during construction (flow meter based on bellows, its compression mechanism and measurement, reproducibility of its volume, pressure and temperature stabilization and measurement, parasitic effects), the method of traceability and the at-tainable uncertainties. [1] ŘEPA, P., TESAŘ, J., GRONYCH, T., PEKSA, L., WILD, J.: Analyses of gas composition in vacuum systems by mass spectrometry. Journal of Mass Spectrometry. 2002 (37), p. 1287-1291. [2] PEKSA, L., GRONYCH, T., ŘEPA, P., TESAŘ, J.: Measuremet of the pressure differences in a large chamber where the pressure is generated dynamically. Vacuum. 2002 (67), p. 333-338. [3] PEKSA, L., ŘEPA, P., GRONYCH, T., TESAŘ, J., PRAŽÁK, D.: Uncertainty analysis of the high vacuum part of the dynamic flow standard. Vacuum. 2004 (76), p. 477-489.

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WS-18-TuM-OR.6 LEAK CALIBRATION BY COMPARISON WITH REFERENCE STANDARD LEAKS. J. M. Hidalgo* and J. L. de Segovia** *Telstar Industrial S. L., José Tapio-las 120, Tarrasa, Spain. ** Instituto de Ciencia de Materiales, CSIC, Cantoblanco, 28249 Madrid, Spain. e-mail: [email protected]/[email protected] For an industrial calibration laboratory the faster and reproducible method for helium leak calibra-tion is by comparing the leak to be calibrated with standard leaks already calibrated at a National Calibration Laboratory or Accredited Laboratory, using a mass spectrometer tuned to Helium gas. In the present work all the possible sources of uncertainties are discussed and they relative contribu-tions presented. Special consideration is given to the problem of the long term satiability contribu-tion. The optimal capacity of measurement is obtained according to the results obtained by applica-tion of the specific calibration procedure.

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WS-18-TuM-INV6.5 LEAK DETECTION: CALIBRATIONS AND REFERENCE FLOWS ARE REQUIRED IN EVERY TYPE OF APPLICATIONS: PRACTICAL EXAM-PLES. A.Calcatelli, Istituto Nazionale di Ricerca Metrologica, I.N.RI.M., Turin, Italy.M.Bergoglio, Istituto Nazionale di Ricerca Metrologica, I.N.RI.M., Turin, Italy D. Mari, Istituto Nazionale di Ricerca Metrologica, I.N.RI.M., Turin, Italy Several methods and related instrumentation are used for leak detection from bubble emission to the ultrasound devices, to pressure/vacuum variation measurements (vacuum gauges, thermal conductiv-ity sensors), to halogen leak detectors or detectors using radioisotopes, to the more recent instru-ments based on selective ion pump detection (SIPD) and finally to the application of mass spec-trometry. The most diffused methods for the leak rates lower than 10-3 Pa m3/s that is based on the application of mass spectrometry with tracer gas (generally helium) is considered (MSLD). MSLD represents the best choice for industrial control of tightening for its good sensitivity and obtainable speed of testing. The leak test may be performed with various methodologies (vacuum, pressure or vacuum-pressure) and its purpose may be to localize the leaks or to quantify them. Leak detection is considered, at European level, by the WG 6 (leak testing) of the CEN/TC 138 (Non Destructive Testing), and worldwide level by the SSCC 66 ““LLeeaakk ddeetteeccttiioonn mmeetthhooddss”” ooff tthhee IISSOO//TTCC 113355 ((Non Destructive Testing). At European level, several standards have been published regarding ter-minology as well as the choice of the method or the calibration of a leak detector and calibration of standard leaks. If the leak detector output must have a real meaning in term of gas flow-rate the instrument has to be calibrated and its uncertainty must be evaluated. Therefore, the calibration of a leak detector is per-formed with reference to known gas flow-rates by using the so-called standard leaks both of permea-tion or geometrical type (generally capillaries) which are used to generate flow from 10

-9 Pa m3/s to 10

-3 Pa m3/s; these standard leaks are calibrated with reference to atmospheric pressure or vacuum

against primary gas flow-meters. The I.N.RI.M. primary flowmeters are shortly described which cover the following gas flow-rate ranges: • 2.10

-9 Pa m3/s e 2x10-8 Pa m3/s with reference to vacuum, extended uncertainty 8%

• 2x10-8 - 3.10-5

Pa m3/s with reference to vacuum, extended uncertainty from 2% to 0.5%. • 2.10-5 Pa m3/s e 1.10-3 Pa m3/s with reference to atmospheric pressure, extended uncertainty 2%. Some calibration results are presented together with the preliminary results of a bilateral comparison which is considered as preparatory for a more wide scale comparison. A device devoted to on line control of components which need that all the significant parameters be well defined starting from the mass spectrometer leak detector which is characterized from metro-logical point of view, that is to say essentially for what concerns linearity and repeatability of the out-put by using reference leaks. The whole machine must be well known in its working configura-tion for what concerns linearity and repeatability and the traceability chain must be made evident.

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JS1-TuM-INV.8 ADDED VALUE NANOSTRUCTURED COATINGS WITH TAI-LORED OPTICAL BEHAVIOUR. C. N. Afonso. Instituto de Optica, CSIC, Serrano 121, 28006 Madrid, Spain. Optical coatings are generally formed by multilayer films whose spectral transmission / reflection are typically controlled through the number of layers, their refractive index and their thickness. How-ever, current applications demand more functionalities such as selective operation depending on in-put conditions (intensity, polarization, etc...), tuneable or ultrafast response, and in many cases, sev-eral functions in the same coating. The design of the structure of the coating in the nanoscale is an attractive route to achieve this goal. This presentation aims to show examples on how nanostructuring allows tailoring the properties of the film or coating to the desired applications. It will first be illustrated through the production of nanocomposite materials formed by metal nanoparticles embedded in a dielectric host that are known to exhibit optical resonances due to dielectric or classical confinement effects. These effects are re-sponsible for colouring of many decorative glasses when the dimensions of the nanoparticles are much smaller than the wavelength of the light. Whereas bulk techniques usually disperse nanoparti-cles randomly, thin film technologies offer the possibility of organising nanoparticles in layers. This layered structure can be then designed in order to achieve the desired response. This concept can straightforwardly be extrapolated to other “dopants” such as ions or different hosts such as glasses or ceramics. Examples will be given on how the optical response of nanocomposite films /coatings can be tuned through the dimensions and separation of the nanoparticles, their “layered” distribution or the use of different hosts. Finally, the possibility of incorporating different functionalities in the same coating either through the use of different “dopants” or pairs “dopants”-host will be illustrated.

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JS1-TuM-INV-7 COATINGS FOR OPHTHALMIC LENSES. T. Vilajuana, Departa-mento de I+D+I INDO, Sta. Eulàlia, 181 08902 L’Hospitalet de Llobregat, Barcelona. Spain. E-mail:[email protected]

Since 1937 Indo is the leading company in the ophthalmic optics Spanish market, and one of the fivemain European companies of the sector. The core activity of the company is the fabrication of spec-tacle lenses, which represents more than 50% of the total turnover. The investment in R&D activitieswas 2.5% of the sales income in 2005 and is planned to increase an additional 4% in 2006. The main requirements of an ideal ophthalmic lens, are lightness, transparency, scratch resistanceand impact strength. Additionally, an ideal lens should be as thin as possible. Organic or polymericlenses have a clear advantage in terms of weight and impact resistance when compared to mineralglass. Nevertheless, a polymeric lens can be more easily abraded than a mineral one. Particularly,high refractive organic lenses can easily be scratched. For this reason, the application of anti-scratchcoatings has become necessary to increase the abrasion resistance of polymeric lenses. Typically, thatcoating is a few micron layer of a composite based on a polysiloxane matrix containing silicananoparticles. This provides the required flexibility and toughness to obtain good scratch resistanceand optimum adhesion of the coating to the lens. An additional benefit of some lenses is that they adapt to light conditions, changing its transmittanceaccording to the amount of light outdoors. The benefit of this photochromic lenses is that they pro-vide a dynamic adaptation to light conditions and a UV protection. This is due to the presence in thelens of molecules that react with UV radiation. The absorption of UV radiation changes the mole-cule’s steric configuration, and consequently absorbing visible light. This is why the lens becomesdark brown or grey, etc. This process is reversible and in the absence of UV light, the lenses becomeclear. Some polymer lenses are casted mixing these photochromic molecules with the lens monomer,while others are applied a photochromic layer in the external surface of a clear lens. Lenses reflect light, since they consist of two optical surfaces that are immersed in an environment ofdifferent refractive index. The higher the difference, the more light is reflected. This light reflected isperceived as ghost images that superpose to natural perception and reduce the quality of vision,which contributes to increase fatigue. These reflections can be practically be reduced with the appli-cation of an antireflective (AR) coating, typically composed of 5 to 7 layers of metal oxides. The first AR coatings easily got dirty and the smudges and fingerprints were more visible and diffi-cult to remove. In fact, many patients found it difficult to keep clean. The application of a hydropho-bic and oleophobic topcoat is a big advantage for these lenses, since they stay cleaner longer thanprevious ones. The composition of that layer is based on a mixture of perluorated hydrocarbons andsilica compounds that repeal water and grease. Since lenses are produced in large quantities, additional concerns like uniformity of optical and me-chanical properties are important key factors in order to decide which technology is used to producethese coatings. Lens reflectance, abrasion resistance, coating durability, hydrophobicity and photo-chromism has to be tightly controlled. Developing new polymer materials with better optical and mechanical properties requires the appli-cation of complex coatings and technologies. The production of millions of them at a competitivecost and in a personalised basis is the challenge of the leading ophthalmic optical companies.

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JS1-TuM-INV.6 SMART OPTICAL WINDOWS OF VARIABLE TRANSPARENCY. E.Matveeva, Universidad Politécnica de Valencia (UPV), Centro Materiales y Tecnologías de MicroFabricación (MTM), Unidad Asociada al Instituto de Ciencias de Materiales de Madrid, Cami deVera s/n, E-46022 Valencia, España The rare earth metals as well as its alloys with magnesium, or proper magnesium alloyed with iron,nickel, manganese, etc. while being put into the contact with hydrogen form metal hydrides whichare wide-band semiconductors transparent in visible range of electromagnetic spectrum. Reversibilityof hydrogenation reaction allows for fabrication of the so-called Smart Optical Windows (SOW) thatchange their reflectivity in function of external impact (application of electric field, change of inten-sity of external light, change of temperature, etc.). The two approaches presently existed are hydro-genation of alloys in gas phase and in liquid phase. The first process is performed in pure H2 and al-lows for achieving a long life-time, mere contrast of reflecting/transparent states and fair reproduci-bility of results. However, it would need pumping the hydrogen in and out to the chamber where hy-drogenating metal is contained. Second approach is related with hydrogenation of alloys in liquidphase under the cathodic bias. Alkaline solutions are mainly used as electrolytes for hydrogenation(typically 1-6M KOH). This is due to the fact that those metals which possess hydrogenation abilityare stable at high pH values, while neutral or acid electrolytes provoke their fast oxidation. Examplesof electrochemical behavior of different hydrogenated materials will be demonstrated during the talktogether with the optical transformations accompanied the hydrogenation/ dehydrogenation proc-esses. The generalized design of the SOW with an electrical control consists of the two thin film electrodesand a conducting media between them. The whole system must be sealed to assure functional stabil-ity and integrity of the device similarly to devices used liquid crystals. One of the electrodes (princi-pal) is hydrogenated and another is the transparent auxiliary electrode that mainly serves as a meansto apply the potential. Due to limitations toward the electrolytes demonstrated by the principal elec-trode (basic conductive media) the second auxiliary electrode must work at the same conditions: im-mersed in 1-6M KOH. Indium-tin-oxide (ITO) gave firstly the impression to be a suitable candidatefor an auxiliary electrode in SOW. Nevertheless, its proper electrochemistry in basic electrolytesgoverned by the mobility of the structural oxygen ions, deep reduction and changes in compositionand conductivity make the SOWs fabricated with ITO as an auxiliary electrode not reliable. Otherapproaches to make conductive a transparent surface (glass/polymer) and exploit possibilities to fab-ricate a sandwich-type device are analyzed. In more advanced SOW technology the use of the polymeric conductive media has been demon-strated. Nowadays, the polymeric electrolytes (or conductive ionic membranes) have extended appli-cations in hydrogen production, separation technologies and electrochemical synthesis. The key pointin the conductive polymers (membranes) is the formation of the highly extended and penetrated net-work of the conductive nano-metric ionic passes formed from the overlapped solvated (hydrated)shells of the functional (acid) groups attached to the polymer chains. The dual character of the re-sulted material (consistency of polymer and conductivity of electrolyte) offers new options in SOWfabrication. The device implemented the Nafion membrane soaked in water and other solventsshowed an acceptable working voltage, good transition to the transparent state and satisfactory life-time under cycling. The principal sources for instability and device destruction are discussed based on the experience ac-quired in the MTM Center of the UPV.

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JS1-TuM-INV.5 TAILORING THE OPTICAL PROPERTIES OF THIN FILMS DE-POSITED BY PLASMA CVD. A. Barranco, A. Borrás, F. Gracia, A.R. González-Elipe. Instituto de Ciencia de Materiales de Sevilla (CSIC-Universidad de Sevilla), c/Américo Vespucio s/n 41092 Sevilla Spain. Plasma Enhanced Chemical Vapour Deposition (PECVD) and plasma treatments are being increas-ingly used for the fabrication of optical films and coatings. The technique offers a wide ranging con-trol of plasma surface interactions, high deposition rates and conformal depositions being fully com-patible with the existing silicon based semiconductor technology and scaleable from the laboratory to the industry. These materials are obtained in the form of single thin films, multilayers, graded index layers, nanocomposites, patterns, and others for applications such as optical filters, antireflective coatings, optical waveguides, wavelength shifters, optical sensors, etc. For these applications is criti-cal the control of the chemical composition and the microstructure of the deposited films. Novel methodologies for the synthesis of optical thin films using plasmas will be presented. The ex-amples cover the control of n and k values in organosilicon thin films, the use of sacrificial poly-meric layers to tailor the microstructure of oxide films deposited at room temperature and the micro-structural control of TiOx and MOx/TiOx optical films. Besides, a novel type of organic and nano-composite fluorescent films deposited from laser dyes will be discussed. These highly functionalized thin films are the basis of a novel photonic materials technology (i.e., photonic filters and sensor on a chip devices). .

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JS1-TuM-.INV.4 FUNCTIONAL AND DECORATIVE REFLECTING LAYER FOR AUTOMOTIVE LIGHTING IN VALEO. J. M. Trigo, R. Acuña, A. Lara and D. Teba, Valeo Iluminación Martos, Calle Linares 15, 23600 Martos, Jaén. Spain. The possible developments of metallization process for reflectors are restricted looking for the qual-ity (maintaining process parameters under control to avoid scraps, creating effective hydrophilic lay-ers to diffuse more an more fogging materials, homogenizing layers thickness) and productivity (re-ducing cycle time, simplifying process steps, decreasing costs and so on). Following the lean process design rules, the trend is to use short dimension machines as Pylonmet (Leybold TM) having short cycle times for PECVD, employing classical materials, as Al for reflec-tive layer and silicone matrix starting from the monomer hexamethyl disiloxane as protective top-coat. This new concept has the advantages of the sputtering system (material long life, good process control for product quality consistency, better adhesion with higher layer density) and the advantages of batch metallization (parts movement and unique chamber). Many efforts are focused to multiply the decorative possibilities of bezels, some of them without re-flective coatings (mass coloured materials where decorated part is obtained directly by injection of pigmented thermoplastics); some others employ coloured reflective coatings by changing the metal itself, creating different chemical reactions with the same metal, giving different colours or with col-oured topcoat. Paint is an usual choice to give decorative effects on bezels because the metallized pigments give us some shining appealing surfaces. On some cases, competitive costs can be achieved in front of in chamber metallization process. Less original effects are achieved masking partially part areas result-ing delimited lines between metallized and non metallized where is visible the natural colour of base plastic. The interaction of YAG laser (wavelength on near IR) and reflective coatings, bring us new and original possibilities for decoration purposes, because laser removes the reflecting layer showing all kind of patterns by contrast with coloured plastic substrate.

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JS1-TuM-INV.3 MULTILAYER COATINGS FOR OPTICAL AND ENERGETIC CONTROL IN GLASSES. F. Villuendas. Departamento de Física Aplicada. Universidad de Zaragoza. 50009, Zaragoza. Spain Architectural trends in the last century drove the use of glass façades in construction, since they pro-vide a lightness aspect to the building, allow the inside-outside communication though the façade andadmit a great variation in the aesthetic aspect. However, the use of glass façades presents several dis-advantages, in particular energetic disadvantages, caused by energy conductive losses with values of5,7 W/m2K in monolithic glass, and by the overheat produced by the excessive solar gain, with val-ues until 500 W/m2 in south orientation. The use of insulating glazing including multilayer sputtered coated glass avoids most of these incon-veniences, giving rise to the development of new products with optimized performances of thermalisolation and energetic solar transmission. So, sputtering technologies and procedures for large areaglass coatings will be reviewed as the first point in this presentation. Several coatings have been designed for optical and energetic control in buildings that are often in-cluded in two big groups, solar control coatings that reduce solar transmission of the glazing andlow-emissivity coatings that reflect infrared radiation while they transmit visible light. Optical andenergetic characteristics are determined by absorptive and infrared reflective properties of metalliclayers together with interference conditions in dielectric layers, so that optical and energetic proper-ties will be dependent on material composition, multilayer structure and thickness of different layers.Typical multilayer structures for both solar control and low-emissivity coatings will be presented,showing the optical and energetic characteristics that can be achieved. The design and development of new multilayer structures with specific energetic and optical proper-ties is the aim of research activities in our group, that has been carried out in collaboration with thecompany Ariño-Duglass. Finally, we present the main features of the design and fabrication proc-esses followed for the development of several specific purpose coatings, including solar control andlow-emisivitty properties, with improved characteristics of different kinds as those concerning ener-getic behaviour, thermal isolation, aesthetic aspect, colour reproduction or chromatic coordinates.

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JS1-TuM-INV.2 SURFACE TREATMENTS FOR INDUSTRIAL GLASSES J.M. Marco.Responsable de I+D. Ariño Duglass S.A. La Puebla de Alfinden, Zaragoza. Spain Glass, as architectural material, has extraordinary characteristics against other transparent materialsin relation to its durability and technical performances. In addition of the intrinsic material character-istics, glass is subjected to different transformation processes in order to achieve a final product thatfulfils all the requirements demanded in actual architecture. Improvements in mechanical resistance,safety against breakage, thermal isolation or solar control, are reached by means of several kinds oftreatments. Some of these important performances are only possible through surface processing tech-nologies. In this presentation, a general overview of the main manufacturing process for industrial glass will beexposed, underlining the common surface treatments used in this sector. A brief introduction toproducts manufactured by pyrolysis and sputtering in order to improve the solar control and thermalisolation will be presented, exposing real application and performance achieved. Another important requirement that glass must fulfil is the control over its aesthetic aspect. Applica-tion of paints and enamels by silkprint, roll coating or digital inkjet systems allows to modify thecolour, texture and visual aspect of glass, customizing each architectonical project. Last develop-ments in float glass decoration and direct application of these products will be presented. Also, laminated glass technologies give the opportunity to modify the general behaviour of glass, inthis sense it is possible to incorporate a coated or decorated PET that expands the uses of glass. Thepossibility to integrate liquid crystal polymers in laminated glass open a way to produce active win-dows. Finally, a prospect about new developments expected in the sector will be outlined.

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JS1-TuM-INV-1 REACTIVE SPUTTERING OF METAL OXIDES AND NI-TRIDES FOR INDUSTRIAL APPLICATIONS. Victor Bellido-González, Benoit Daniel, Sarah Powell GENCOA, Physics Road, Liverpool L24 9HP (UK). E-mail: [email protected]

Magnetron sputtering has become one of the key industrial vacuum coating technologies in re-gards to many of today’s applications. In magnetron sputtering, a material called target (e.g. Ti), suffers ion bombardment by ions of a mainly inert gas (e.g. Argon) and in that bombardment ma-terial is removed and transported onto a desired surface to be coated. The plasma trap around that target is based on a electric-magnetic cross field (ExB). Some of these processes also involve the reaction between the element or elements of the target material and a gas. That reaction produced a coating of very different nature to the target material itself and the process is called reactive magnetron sputtering. Two groups of these reactive gases are Nitrogen which will give as a re-sult a nitride of the elements of the target (e.g. TiN) and Oxygen which will give as a result an oxide of the elements of the target (e.g. TiOx). In some cases the target itself is of a oxide or ni-tride nature and generally some sort of degree of reactive sputtering is maintained in order to tay-lor specific coating properties (e.g. Ito target sputtering in atmospheres containing O2 or H2). In this presentation some of the current issues in the control of such processes will be exposed. Also practical applications of oxides and nitrides will be explained based on our industrial experience. These will include multilayer oxides for optical coatings, transparent conductive oxides for photovoltaic and display technology, oxides for scratch resistance technology, nitrides for deco-rative and hard coat applications, solar-thermal absorbers, etc. A short comparison with some other technologies such as cathodic arc will be exposed as these technologies can be sometimes found competing on a similar ground of applications.

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TuM-Pl.2 THE ROLE OF ENERGETIC IONS IN THE DEVELOPMENT OF MUL-TILAYERED X-RAY REFLECTION OPTICS. J. Verhoeven, FOM AMOLF, Kruislaan 407, 1098SJ Amsterdam, The Netherlands Since the seventies of the past century multilayer systems at nanometre scale have been applied as spectroscopic elements for wavelengths > 0.1 nm as well as optical reflection systems in the short wavelength region (<100 nm). These optical applications include the lithographic produc-tion of electronic components (13.6 nm) as well as microscopy in the “water window” (2 – 4.4 nm). Main requirements are a high optical contrast for the multilayer components in the wave-length region of application and a density profile with sharp interfaces between the components. There are two causes for a deviation from sharp interfaces, the development of surface rough-ness during deposition of the multilayer components and the formation of interlayers due to in-termixing of these components. The development of surface roughness depends on the materials combination in relation to the physics of layer growth with as external parameters deposition rate and energy input. A high chemical reactivity combined with an elevated temperature, is the cause for formation of interlayers. For the whole process of deposition, ion etching and implantation, a UHV chamber (p<10-8 mbar) with an e-beam evaporation system and a Kaufman broad beam ion source was available. Accurate real time thickness monitoring during deposition as well as ion treatment was achieved from interference of in situ reflected N K or C K radiation. The behaviour of the reflected inten-sity during the processes provided also information about the surface roughness development during the whole process of deposition and ion treatment. Auger Electron Spectroscopy was used to determine the composition of the surface of a deposited layer and to perform depth pro-filing. An improvement by a factor of 3 for the reflectivity of N K radiation by a 3.8 nm W/C multi-layer was obtained after removing an excess layer of W by 1.4 nm for each period using 300 eV Ar+ ions. This was ascribed to a reduction of the surface roughness by removal of loosely bound W atoms. The reflection of 6.7 nm Mo/Si multilayer systems was optimized by removal of 1.5 nm Si for each period using 300 eV Kr+ ions. Smoothing of the Si surface was explained by vis-cous flow of the whole layer. The Mo on Si interface turned out to be much more sensitive for ion induced intermixing than the Si on Mo interface. It was demonstrated that a controlled Mo5Si3 layer with sharp interfaces could be produced by ion beam intermixing. Implantation of low energy C+ ions into Si was applied to form a SiC interlayer in order to reduce the chemical reactivity with Mo, improving the thermal stability. In contrast, the W on Si interface of W/Si multilayers appeared to be less sensitive for ion induced intermixing. Moreover, it appeared that controlled intermixing resulted in an interlayer with a gradient density. For the highly chemical reactive Ni/Si combination implantation of N+ ions into Si combined with controlled intermixing of the Si on Ni interface was successfully applied to obtain a stable multilayer system. Finally a combination of deposition, C+ ion implantation and annealing was applied to form Si/SiC multi-layers with a periodicity of 16 nm. Initially implantation only resulted in the formation of a 0.6 nm thick SiC layer within a Si/C mixture. After annealing at 7500C an amorphous carbide layer with a thickness of 4.4 nm was formed. Annealing at 10000C caused crystallisation of this amor-phous layer. For all applications the ion energy is limited by the penetration depth in related to unwanted intermixing at the interface with the component underneath.

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TUESDAY MORNING

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JUNE 26 MONDAY AFTERNOON

WS-18-MoA-OR 5 DYNAMIC EXPANSION SYSTEM AT CEM. C.Matilla; N.Medina; S.Ruiz. Spanish Centre of Metrology (CEM). The Spanish Metrology Centre has an orifice-flow primary pressure standard. In this kind of pressure standard a known flow of gas passes through an orifice of calculated conductance creating a pressure gradient between both sides of the orifice. The known flow of gas is generated by a precision flow-meter which can work using the constant volume method or the constant pressure method. Since its construction the system has suffered several modifications in order to improve its results which will be described as follows. The first flowmeter was manually operated. That is the reason why it could basically be used with the constant volume method. Nowadays it has been completely automatised and it uses the constant pressure method, which is much more accurate. Data acquisition software has been designed to monitor all the parts of the system involved. Some parts of the flowmeter have been correctly isolated by means of aluminium walls to stabilise their temperature. The first vacuum pump connected to the vacuum chamber was a 300l/s turbomolecular pump. At present it has been replaced by a 700 l/s turbomolecular pump which allows the system to be closer to ideal conditions as well as to obtain an appropriate base pressure more easily.

52


WS-18-MoA. OR.4 LONG TERM SHIFT IN CAPACITANCE GAUGES: CONTRIBUTION TO THE TOTAL UNCERTAINTY. J. M. Hidalgo* and J. L. de Segovia** Telstar Industrial S.L. José Tapiolas 120, O8226 Terrassa Spain.** Instituto de Ciencia de Materia-les,CSIC,Cantoblanco,28240Madrid,Spain e-mail:[email protected]/[email protected] One of the contributions to total uncertainty in capacitance gauges is the shift of long-term stability. This contribution can be only determined by recalibrations usually with a periodicity of one year. Inthe present work, we present a study of the “shift” of four capacitance manometers ranging from 1000mbar to 10-3 mbar. Recalibration of the reference standard took place at two National Laboratories with one-year periodicity and for a total time up to six years depending of the gauge. This is an enough extended period to obtain some conclusions about the long-term stability in this kind of gauges. Based on their principle of working the higher contribution to the “shift” is expected from thefatigue of the material of the membrane. The deviation i.e., the difference between the readings ofworking standard of the National Laboratory and the calibrating gauge, are also discussed. The several contributions to the total uncertainty are presented and compared with the uncertainty due to the shift.As consecutive recalibrations are not performed at the same calibrating points in the primary standard of the National Laboratory, it is necessary to perform interpolations to obtain the differences of the readings at the same calibrating points, uncertainty considered in the final expanded uncertainties

51


WS-18-MoA.INV.4 CALIBRATION OF PRESSURE SENSORS IN AN INDUSTRIAL ENVIRONMENT. M. Wüest, INFICON Ltd., Alte Landstrasse 6, LI-9496 Balzers, Liechtenstein National Measurements Institutes calibrate vacuum pressure sensors a few gauges at a time in a labo-rious and time consuming fashion resulting in an accurate calibration with small error estimates. A manufacturer produces a comparatively large number of sensors a day which must be economically calibrated. Therefore, a manufacturer of vacuum pressure gauges can not spend the same amount of time at a calibration. Here, we describe a procedure to calibrate vacuum gauges rapidly and cost effi-ciently. Maintaining the calibration in an industrial environment is another challenge. Vacuum gauges are calibrated in the factory in a clean environment with nitrogen. However, during the use of the gauge, the sensor may encounter an environment which causes coating or etching of sensor ele-ments. This leads to degradation of the sensor with time and inaccurate pressure readings, but may be difficult to detect. I will describe examples of contamination and some of the counter measures.

50


WS-18-MoA-INV.3 CLEANING PROCESSES AND QUALITY CONTROL FOR VAC-UUM. R J Reid, ASTeC, CCLRC Daresbury Laboratory, Warrington WA4 4AD, UK Cleaning is an important part of the processing of vacuum components and systems for any level of vacuum. However, the lower the pressure required, the more stringent the cleaning requirements must be. Over recent years, many of the traditional processes used for cleaning have become unacceptable be-cause of their effect on the environment and, indeed, many have been prohibited by legislation. In this paper, an outline will be given of the search for the “perfect” cleaning process for UHV and XHV components which is effective, economical and likely to remain acceptable. We shall discuss what has become the industry standard use of aqueous detergent based techniques and the use of some of the newer solvents which have been developed. Of course, the search for a “perfect” process leads us to pose the question “How do we know when a system is sufficiently clean?” Some answers to this question will be discussed. This will then lead us to look at implementation of quality control procedures to ensure that an “as delivered” component will be satisfactory for purpose. Examples will be given, including that of a very large XHV vessel currently being manufactured in Germany.

49

WS-18 SESSION

48


RIVA-TF-MoA-OR.16 DUAL DC MAGNETRON CATHODE CO DEPOSITION OF (Al, Ti) AND [(Al, Ti) N] THIN FILMS WITH CONTROLLED DEPTH COMPOSITION. Y. Nunes, A. Wemans, H. P. Marques, Q. Ferreira, O. M. N. Todoro and M. J. P. Maneira. Cefitec - Department of Physics, Faculty of Sciences and Technology, New University of Lisbon, P-2829-516, Caparica, PORTUGAL. Recent publications show that [(Ti, Al) N] thin films produced with direct current reactive magne-tron sputtering can significantly improve electrochemical and biocompatibility properties of the base metal alloy. The purpose of this work is to study the characteristics of titanium-aluminium nitride [(Ti, Al) N] films produced using a novel coating technique. Thin (Al, Ti) films with a linear gradient depth composition are obtained from a custom made code-position system which employs pure Al and Ti sputter targets. Two direct current magnetron cath-odes with independent plasma sources are simultaneous controlled by custom LabView software which allows real-time and independent control of the deposition parameters for both cathodes. Two types of gradient thin films were produced. Starting with 100% Al at bottom and 100% Ti at surface and starting 100% Ti and ending with 100% Al at surface. Both types of films are of 500nm thin. Depth profile was acquired using secondary ion mass spectrometry (SIMS). These films of (Ti, Al) and [(Ti, Al) N], have been grown onto Mg, Glass and Si (100) substrates, the first in argon at-mosphere and the later in nitrogen. Further analysis will be carried using atomic force microscopy to investigate the surface morphology and X-ray photoelectron spectroscopy (XPS) in order to detect possible chemical interactions be-tween the film compounds.

47


RIVA-TF-MoA-OR.15 OXIDE THIN FILM COATINGS BY SPRAY PYROLYSIS ONTO STEEL COILS. R. López Ibáñez. Departamento de Física Aplicada I, Facultad de Cien-cias, Universidad de Málaga, E-29071 Málaga, Spain. F. Martín. Departamento de Igeniería Quími-ca, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain. J.R. Ramos-Barrado. De-partamento de Física Aplicada I, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain. D. Leinen. Departamento de Física Aplicada I, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain. A large scale spray pyrolysis coater has been designed and constructed for industrial pilot trials in the aim of depositing different functional metallic oxide thin films onto metallic substrates, such as antireflective layers, self-cleaning films, barrier layers, selective thin films, photocatalytic coatings, etc. Within the field of solar thermal energy, a zirconia film has been produced onto an aluminized steel coil of 0.4 m width which has been previously coated with a selective layer elsewhere. The zir-conia film as a top-coat has the function of anticorrosion and protection against ambient impact in outdoor conditions. Technical details: Zirconium acetyl-acetonate in a 0.02 molar aqueous solution was used as precur-sor for spraying onto the 200º C heated substrate, growing in these conditions aproximately a 10 nm thick zirconia thin film. After several coating repetitions an 80 nm ZrO2 thin film was produced. Characterization: UV-Vis-NIR-MIR hemispherical reflectance spectroscopy showed that the zirconia coating is highly transparent and acts as an antireflection layer, increasing the solar absorptance in about 10 %, but not degrading the thermal emittance at 373K, thus improving optical properties for a solar thermal device. SEM revealed a dense film which covers well the substrate sealing existing pores. No cracks could be seen on the surface of the coating even after repeating the coating process for several times, rolling up and unrolling the steel belt from its cylindrical storage. XPS depth pro-file analysis showed that the material was well pyrolysed to zirconium oxide. Only 3% of carbon re-maining from the precursor was found inside the film, stabilized in a ZrC phase homogeneously di-luted across the zirconia film thickness. No crystalline structure was detected by XRD. Linear po-larization measurements were carried out in 0.5 molar sodium chloride aqueous electrolyte solutions. A reduction in the registered current densities showed a decrease in corrosion attack by approxi-mately one order of magnitude when comparing to the corrosion behaviour of the substrate itself. Conclusions: Compact, homogeneous and well synthesized zirconia thin films have been deposited onto a continuously moving steel belt with an industrial scale spray pyrolysis pilot station. The zir-conia film improves corrosion resistance and the optical properties of the layer stack, zirconia top-coat, selective layer, aluminized steel substrate, with regard to solar thermal applications. Acknowledgements: Funds from the EU (project SOLABS: ENK6-CT2002-00679) are gratefully acknowledged. EU Project SOLABS: Development of unglazed solar absorbers (resorting to coloured selective coatings on steel mate-rial) for building facades, and integration into heating systems. www.solabs.net

46


RIVA-TF-MoA-OR.14 STUDY OF THE EFFECT OF SILICON EXCESS AND ARTIFI-CIAL AGEING ON THE MICROSTRUCTURAL STABILITY OF Al-Mg-Si ALLOYS. Y. Aouabdia*, Boubertakh ABDEL HAMID*, Hamamda SMAÎL*. *Laboratoire des Propriétés Ther-modynamiques et des Traitements de Surface des Matériaux. Faculté des Sciences, Université Men-touri-Constantine Route Ain El-Bey, 25000 Constantine, Algérie

[email protected]

The use of Al based alloys for automotive body materials has been driven by a number of issues, inparticular weight saving. We are interested in in Al–Mg–Si alloys with excess Si. For this work, westudy the effect of excess Si on the precipitation of the β’’ phase. Samples from an Al–Mg2Si–0.5%Swere studied by differential scanning calorimetry (DSC), optical microscopy, Vickers hardness testing, and MEB. Data on reaction kinetics, grain size, and micro-hardness are analyzed with referenceto a stoichiometric alloy. This study revealed that excess Si increases the activation energy for the reaction, and globally improves the mechanical properties of the alloy. The precipitation sequence in theAl-Mg-Si alloys with excess silicon is generally accepted to be:

clusters of solute atoms GP zone I GP zone II/ β” β’ β (Mg2Si)+Si Key words: Al–Mg– Si alloys, excess Si, precipitation, activation energy, β'

45


RIVA-TF-MoA-OR.13 BREAKDOWN VOLTAGE IN MAGNETRON DC GLOW DIS-CHARGES. THE INFLUENCE OF THE MAGNETIC FIELD. Y. Nunes, A. Wemans, P. R. Gordo and M. J. P. Maneira. Cefitec - Department of Physics, Faculty of Sciences and Technology, New University of Lisbon, P-2829-516, Caparica, PORTUGAL. In abnormal glow discharges with magnetic field, the electrons are confined in a trap near the cath-ode allowing work at lower pressures and voltages. For thin film applications this can influence posi-tively the quality of the sputtered film and decreases the processing time.

In this work breakdown voltages of the abnormal glow discharges of argon on copper with magne-tron assistance, are measured for different magnetic configurations. To achieve this, a cathode, shown in Fig.1, was constructed with a magnetic circuit, based on perma-nent NdFeB, which can be systematically moved allowing fine control of magnetic field distribution, see Fig.2. This way the influence of the magnetic field in the plasma parameters and in particular the influences in the breakdown voltage are studied. The breakdown voltages are measured and presented as a function of pressure for different distances of the magnetic circuit to the target. The study takes in account a range of pressures from 0.2 to 32 Pa and a range of the parallel component of the magnetic induction, from 0.3 T to 1.7 T at the target surface. The expression,

PCCeCPV CP

B ⋅++⋅=−

4312)(

fits the data of breakdown voltage dependence on the working pressure, with high correlation coeffi-cient and the constants depend on magnetic distribution At each magnetic configuration the first exponential term accounts for low pressure range and the linear term accounts for the higher pressure range. Minima similar to what happens in Paschen’s Law, are observed which shifts to lower pressure with increase of the magnetic field. This behavior is systematic and regular.

dd

Fig1. Cathode mounted in the system and the copper discharge on argon.

Fig2. Magnetic circuit position inside the cathode body

44


RIVA-TF-MoA-OR.12 STRUCTURAL, ELECTICAL AND OPTICal PROPERTIES OF INDIUM-TIN-OXIDE THIN FILMS preparED by pULSED LASER DEPOSITION. A. Khodorov, M. Piechowiak* and M.J.M.. Gomes. Physics Center, University of Minho, 4710-057 Braga, Portugal. *Department of Material Science, University of Silesia, 41-200 Cosnowiec, Poland Indium-tin-oxide (ito) films show an interesting and technologically important combination of prop-erties: excellent substrate adherence, hardness, chemical inertness, good electrical conductivity and high transparency in the visible range of electromagnetic spectrum. for using ito films as transparent electrodes to grow multilayer structures the crystalline quality and preferred orientation of domains in the films are very important. In this work we prepared ito thin films by pulsed laser deposition at different temperatures (from 24 up to 600oc) with several oxygen pressures on glass substrate. the texture selection and cell parame-ters were studied with help of x-ray diffraction. the sheet resistance was determined by a four-point-probe method at room temperature. the optical properties were examined in the wave-length range 200 - 3200 nm. the dielectric function of ito film was obtained by fitting the measured transmission and reflection spectra to a dispersion relation, which combines the drude model and lorentz oscilla-tor. the well crystallized, highly textured and highly transparent films were grown at high tempera-tures. variation of substrate temperature as well as oxygen pressure during deposition results in dif-ferent structural, electrical and optical properties. the correlation between deposition conditions and physical properties of ito films was observed and analysed. This work was supported by fct (grant sfrh/bpd/11675/2002)

43


RIVA-TF-MoA-OR.11 ADSORPTION PROPERTIES, MICROSTRUCTURE AND OP-TICAL BEHAVIOUR OF TIO2 THIN FILMS PREPARED BY PECVD. A.Borrás, A. Bar-ranco, J. Cotrino, A.R. González-Elipe. Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla). Avda. Américo Vespucio s/n. 41092 Sevilla (Spain)

It is a common place that the type of microstructure of thin films is critical for an effective control of their optical properties. Usually, the microstructure is monitored by direct observation by SEM and related microscopies. Recently, the use of spectroscopic ellipsometry under controlled ambient con-ditions to measure adsorption isotherms has become an interesting technique to asses the type of po-rosity in the films. In the present paper we discuss the possibilities of the adsorption isotherm tech-nique measured by means of a quartz crystal monitor (QCM) to asses the porosity of TiO2 thin films prepared by PECVD under different conditions. The microstructure and optical properties of the films have been also characterized by SEM and optical methods. A large variety of TiO2 thin films with different microstructures and optical constants (n ranging from 1.8 to 2.2) have been obtained. SEM gives information about the type of microstructure developed in the films (columnar, globular, homogeneous, etc.). In addition, the water isotherms measured with the QCM provides important in-formation about the type of pores present in the films (i.e., micro, meso or macro pores) and the pore size distribution. The analysis of the reversibility of the adsorption processes, as well as the depend-ence of the adsorption characteristics as a function of the thin film thickness, have furnished impor-tant clues to explain the optical properties of the films and their dependence on thickness. Small variations of the optical constant of thin films exposed to the atmosphere can be also explained by realising the irreversibility of some of the adsorption processes under ambient conditions. The use of adsorption isotherms of vapours to characterize the porous structure of thin films can be considered as an universal tool for the porous characterization of these materials providing comple-mentary information on the microstructure of the films

42


RIVA-TF-MoA-OR.10 THE INFLUENCE OF MAGNETIC CONFINEMENT IN DI-RECT ABNORMAL GLOW DISCHARGES. Y. Nunes, A. Wemans, P. R. Gordo and M. J. P. Maneira. Cefitec - Department of Physics, Faculty of Sciences and Technology, New University of Lisbon, P-2829-516, Caparica, PORTUGAL. In this work an experimental study of the magnetic field influence on planar magnetron abnormal glow discharges of argon on copper targets is presented. A magnetron cathode that allows the control of the magnetic configuration was developed, and its magnetic circuit characterized. To quantify the magnetic field influence in the discharge, a confinement power parameter CB, was defined. This parameter, takes into account simultaneously the useful volume of the field, VC, and the average of the parallel component of the magnetic induction to which the plasma is subjected. For a planar magnetron cathode with cylindrical symmetric magnetic field, where r and z are the ra-dial and height coordinates, and B|| the parallel component of the magnetic field in this coordinate. The confinement power parameter is:

rdrdzzrBCCV

B ),(2 ||∫∫= π

Current-voltage-pressure characteristics were measured and the influence of the confinement power is mapped through current-voltage curves at constant confinement power values, displayed at several pressures. It was showed that at higher confinement power values the behaviour of the I-V character-istics is in general well described by the Thornton empirical law, I=kVn. Systematic study of k and n Thornton parameters with confinement power will be presented. The re-sults show that above certain value of CB, the Thornton parameter, n, that is considered to character-ise the entrapment efficiency of the electrons, converges to a constant for pressures from 1 to 8 Pa, as can be seen in Fig1.

The data shows also that there is dependence between n and k, Thornton parameters.

Fig.1 – Thornton parameter n as function of confinement power CB.

41


RIVA-TF-MoA-OR.9 INFLUENCE OF PRESSURE ON THE STRUCTURAL ME-CHANICAL AND DECORATIVE PROPERTIES OF TiN THIN FILMS DEPOSITED BY CATHODIC ARC EVAPORATION. A. Lousa, J. Esteve. Departamento de Física Aplicada y Óptica, Universidad de Barcelona, Avda. Diagonal 647, E-08028 Barcelona, Catalunya, Spain. J.P. Mejia, A. Devia. Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Maniza-les, Campus La Nubia, Manizales, Colombia. Titanium nitride TiN is one of the hard materials most widely studied and commonly used as decora-tive coatings, wear-resistant coatings, diffusion barriers and electrodes in industrial applications. TiN coatings are deposited by different PVD and CVD deposition techniques. The typical gold color of TiN makes it an attractive candidate for decorative applications. TiN can be obtained in a relatively wide range of compositions around stoichiometry. Changing the stoichiometry around the 1:1 com-position broadens the spectrum of colors and can modify the mechanical properties compared with those of stoichiometric TiN. Cathodic Arc Evaporation (CAE) is a especially attractive PVD deposition technique both for its unique abilities (highly ionized vapor which allows ion energy control through substrate bias volt-age, high deposition rates, excellent adhesion), and for been widely use in industrial applications. It is well known that composition, structure and properties of the deposited films depend on the process parameters such us growth temperature, substrate bias voltage, gas pressure in the vacuum chamber. The purpose of this work is to study the feasibility of depositing TiN coatings of different gold tones with good mechanical properties by using a metallic Ti cathode and varying the nitrogen partial pres-sure in a CAE reactive process. This pressure was varied between 5x10-4 and 3x10-2 mbar. The other technological parameters were kept fixed for all the samples at the following values: cathodic cur-rent, 60 A, substrate temperature 400 ºC, substrate bias voltage, -300 V. The coatings were deposited on polished steel substrates. The resulting film thickness varied between 1-2 microns, with high deposition rates which ranged from 8 μm/h for the samples deposited at low pressure, to 4 μm/h for the samples deposited at high pressure. The composition of the coatings studied by XPS indicates an increasing nitrogen content as the nitrogen partial pressure is increased. SIMS analysis shows that this composition is uniform throughout the coatings thickness. The crystalline structure was studied by XRD which shows typi-cal diffraction patterns corresponding to polycrystalline TiN. The evolution of the crystalline struc-ture with pressure is discussed in terms of grain size and preferred orientation. The color characteris-tics of the samples were analyzed by spectral reflectometry in the visible range. The reflectivity spectra show a gold-like shape with significant shifts that correlates to the nitrogen content in the samples. The mechanical properties of the coatings were characterized by dynamical nanoindenta-tion (NanoTest 550, Micro Materials Ltd.) with a Berkovich diamond tip. The hardness and Young’s modulus values were obtained by the Oliver and Pharr analysis method. The Young modulus values resulted close to the bulk TiN value (310 GPa). The hardness of the coatings increases with nitrogen pressure until reaching a maximum of 24.5 GPa at 1.3x10-2 mbar, in the intermediate zone of the studied range, and decreasing for higher pressures. In summary, we have shown that the control of the nitrogen pressure is useful to obtain TiN coatings with a wide palette of gold colors and good mechanical properties.

40

RIVA-TF SESSION

39


ETCHC-MoA-INV.3 THERMAL BEHAVIOUR OF W-SI-N HARD COATINGS IN PROTECTIVE AND OXIDATION ENVIROMENTS. A. Cavaleiro, ICEMS -Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Dep. Eng. Mecânica, Rua Luís Reis Santos, 3030-788 Coimbra, Portugal Extensive discussion has been raised concerning the structural arrangement in TM-Si-N (TM=transition metal) nanocomposite coatings, particularly on the way how Si is present in the coat-ings. Furthermore, abundant results on the hardness and Young´s modulus of these films is available in the literature, particularly for TM = Ti and Zr. As a function of the phase arrangement, different interpretations and discussions on the hardening mechanisms involved in the mechanical behaviour of the coatings, have been raised such as, grain size, residual stress, lattice distortion. Many authors defend that the hardness of TM-Si-N films depends only on the purity, dimensions and distribution of the Si-N phase in relation to the TM nitride grains. W-Si-N is a particular case in the world of TM-Si-N systems (TM=Ti, Zr), due to the different chemical affinity among the elements. In fact, the affinity of N for W is much lower that the one of Si, inversely to the case of e.g. Ti-Si-N where similar affinities of Ti and Si for N are observed. Such a fact determines the arrangement of the phases during the deposition and has a huge influence on the structural stability of the coatings when annealed at increasing temperatures. The main conse-quences are: (1) much higher N2 partial pressures are needed for depositing films with W-nitride phases and (2) after thermal annealing no W-nitride is detected in the films. However, the coatings of this system can also show hardness values as high as 45GPa even if the main phase (W-based) his typically a metallic bonding type based material.. In this talk, the current knowledge on the thermal annealing of W-Si-N sputtered films in both pro-tective and oxidant atmospheres is reviewed. Firstly, sputter deposited single W films are presented as a particular case of metallic element films and their thermal annealing analyzed. The transition for the W-Si-N films permitted to conclude that the addition of Si promotes a loss of the crystallinity de-gree until amorphous structures are reached. Generally, amorphous coatings (20-30GPa) are softer than crystalline ones (25-45GPa). Afterwards, the thermal stability of W-Si-N coatings is considered either in protective or oxidant atmospheres. Special attention is paid for amorphous films. In protec-tive atmosphere, it is shown that after crystallization the hardness can be higher than that of as-deposited crystalline films with similar structure. The hardest films have a single W-metallic phase mixed with amorphous Si-N phase. The Si content is determinant in the oxidation resistance: the higher the Si content the lower the oxi-dation rate is. As an example, the weight gain reached by a coating without Si at 650ºC is similar to the one shown by a high Si content film (>30at.%) at 1000ºC. The oxidation resistance is attributed to either the formation of a continuous protective Si-rich layer or to the synergetic effect of a very low oxide grain phase and a very high compactness of the oxide scale.

38


ETCHC-MoA-OR.10 MODIFICATIONS OF TRIBOLOGICAL BEHAVIOUR OF STAINLESS STEELS BY DUPLEX TREATMENTS. R. J. Rodriguez, J.A. Garcia, R. martinez, G. G. Fuentes. AIN. Centro de Ingeniería Avanzada de Superficies. 31191 Cordovilla, Pamplona, Spain Ordinary PVD coatings exhibites adequate properties from the point of view of hardness, friction or wear coefficient to provide a solution good enough for many of the problems. However, they are 2 – 5 μm thick, a limit that can not be surpassed due to internal stresses that lead to crack formation and delamination. In addition, soft substrates like stainless steels are not adequate to be coated by a hard material (hardness beyond 15 GPa), because the plastic flow of the substrate induces the fracture of the hard coating even at medium contact pressures. DUPLEX treatments (ion nitriding + PVD coatings) have been proposed as a solution for the treatment of metal alloys like, stainless steels, titanium alloys or, even, aluminium alloys, as well as tool steels. Most of PVD industrial systems could be adapted to provide an ion nitriding treatment prior to the PVD deposition process. Both treatments can be applied in the same chamber, without breaking the high vacuum conditions to prevent contamination. This papers reports the results obtained on on AISI 304 and 316 stainless steels by a DUPLEX treatments: Ion nitriding + PVD coating. An adapted arc-evaporation PVD coater has been employed to produce nitrided layers of 10 – 20 μm with different process parameters, by employing an original nitriding process based on the AEGD configuration. The same equipment has been used to subsequently deposit the PVD coatings. GD-OES analysis and FE-SEM inspection have allowed to characterise the main features of DUPLEX treatments in comparison with ordinary coatings. Changes in roughness, micro-hardness, adhesion, friction and wear coeficcients have been measured. As an overall conclusion, both DUPLEX treatments have shown improved properties and better behaviour. KEYWORDS PVD, nitriding, duplex treatment, tribology.

37


ETCHC-MoA-OR.9 CHANGES DETECTED IN ECR-CVD AMORPHOUSAND NI-TROGENATED AMORPHOUS CARBON FILMS BY INCREASING PLASMA ION ION ENERGY. J.G. Buijnsters, M. Camero, L. Vázquez, C. Gómez-Aleixandre, J.M. Albella, Instituto Ciencia de Materiales, CSIC, Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain Hydrogenated amorphous carbon (a-C:H) and nitrogenated amorphous carbon (a-CN:H) thin films may present interesting properties like high smoothness, low friction coefficient, high hardness and high wear resistance which make them excellent candidates for different applications. a-C:H and a-CN:H films have been grown from methane/argon and methane/nitrogen/argon gas mixtures respec-tively by Electron Cyclotron Resonance Chemical Vapour Deposition (ECR-CVD). During the deposition process, a negative DC bias voltage was applied to the substrate in order to obtain high energy ions arriving at the growing surface. The effect of the ion energy on the structural, morpho-logical and mechanical properties of the films has been explored by multiple analysis techniques. The obtained results clearly show a sharp change in the properties of the a-C:H and a-CN:H layers from a threshold ion energy in the order of 100 eV for the production of hard, low-friction coatings. For no bias application or bias voltages more positive than –100 V, cauliflower shaped and relatively soft polymeric (nitrogenated) carbon films are formed. The change in the properties of the films de-posited in the two distinct deposition regimes has been associated with the new nanostructure of the films detected by surface analysis techniques.

36


ETCHC--MoA-INV.2 NANOSTRUCTURED PVD COATINGS ON THE VERGE OF INDUSTRIAL APPLICATIONS. Rafael J. Rodríguez, José-Antonio García, Gonzálo García and Rosario Martínez. AIN. Centro de Ingeniería Avanzada de Superficies. 31191 Cordovilla – Pam-plona, SPAIN. The search for new high performance coatings has experienced a relevant progress due to the recent attention paid to the properties of nanostructured materials. In the last ten years a huge amount of re-sults have been published describing how nanostructured PVD coatings may exhibit excellent com-binations of different properties, including super- or ultra- hardness, extreme wear resistance, higher toughness and corrosion resistance. Most of these results have been achieved at laboratory scale. It seems that there is a real difficulty to scale up these promising findings to exploitable industrial applications. By the way, this has been not any obstacle for employing the mark “nano-“ in many commercial names of new coating introduced in the market in the last five years. This paper intends to make a review of most interesting strategies employed for the research groups: nano-multilayers and nanocomposites approaches. A critical revision of the claimed new properties is made, paying special attention to their possibilities of industrialization. Related problems like techniques and standards to measure the coatings characteristics are also reviewed. Keywords: PVD, multilayers, nanocomposites, industrial applications.

35

ETCHC SESSION

34

MONDAY AFTERNOON

33

JUNE 26 MONDAY MORNING

WS-18-MoM-OR.3 NEUTRAL PRESSURE MEASUREMENTS IN TJ-II PLASMAS. F.L Tabarés, D. Tafalla and J.A. Ferreira. Laboratorio Nacional de Fusión por Confinamiento Magnético, CIEMAT, Avda Complutense 22, Madrid The density of neutral species in the periphery of a hot plasma, such as in those generated for Fusion research, represents a net particle source, ideally in equilibrium with the recycling flux of particles escaping the plasmas due to limited magnetic confinement. Its measurement in Fusion plasmas is of crucial interest in particular when divertors are used for the control of the particle and power out-flux, and several concepts have been put forth for its recording (1). In limiter devices, however, its measurement has always been rather problematic. This is mostly due to the difficulty in defining the concept of pressure itself under such anomalous conditions, i.e., in the region between the hot plasma and the walls, where strongly non-thermal equilibrium conditions prevail. Even so, the recording of the manometer readings during the plasma production can provide very useful information about the particle confinement and recycling. In the TJ-II stellarator (2), a set of manometers, including Bayard-Alpert gauges and baratrons, is routinely used for the control of the particle fluxes injected into the plasma. Recently, the direct reading of the pressure evolution during the plasma shot at re-gions away from the gas injection ports has also become available. Neutral pressures values in the order of 10-5-10-4 mbar have been recorded, depending on plasma heating and wall recycling condi-tions. In this work, the technique of measurement and the interpretation of the readings will be de-scribed. The implications for the density control of the plasma and the possible improvements for fu-ture analysis of the particle out-flux will be also discussed. 1. H.F. Dylla. J. Vac. Sci. Tech. 20 (1982) 119 2. F.L Tabarés, A. García, J. Botija, 45 Vacuum (1994) 1059

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WS-18-MoM-INV.2 VACUUM STANDARDS AT CEM. C. Matilla. Spanish Centre of Metrology In the next future CEM will have three different vacuum standards to cover all the vacuum range. These standards are a dynamic expansion system, a static expansion system and a forced balance pis-ton gauge. The dynamic expansion system is based on the known orifice flow technique in which a flowmeter is used to generate a known flow rate of gas in a vacuum chamber partitioned by an ori-fice of calculated conductance. It has been working for some years but it has suffered several modifi-cations to make it more accurate. The forced piston balance is a recent acquisition. It is a pressure standard designed to cover the range from less than 1 Pa to 15 kPa gauge and absolute pressures. The instrument operates on the piston gauge principle in which the pressure on the piston is measured by a forced balanced load cell. We were encouraged to acquire it by the good results obtained by other metrology institutes. At the moment we are testing its performance and we are satisfied with its re-sults. The static expansion system is based on Boyle´s law with corrections. It is a project in collabo-ration with EUITT (UPM), which has been founded by the R&D National Plan. This project will be finished in 2008.

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WS-18-MoM-OR.2 NUMERICAL MODELING OF THE ION BEAM TRANSMIS-SION EFFICIENCY FOR DESIGN OF THE VACUUM SYSTEM OF THE DC-60 CYCLO-TRON. A.V. Tikhomirov, G.G. Gulbekian, B.N. Gikal. Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow region, Russia. The results of a numerical simulation of the transmission efficiency of ion beams in conditions of ion recharge on the residual gas in the channel of the axial injection, in the DC-60 cyclotron vacuum chamber, as well as in transport lines of accelerated beams are presented. The computer modeling programs GENAP and VACLOS have been used. They have been developed and tested on the basis of experiments on four cyclotrons of heavy ions of the Flerov Laboratory of Nuclear Reactions. They also have collected an experience of vacuum systems’ design of a number of projects for both design of new cyclotrons and their upgrade. The simulation programs estimate ion beam losses on the basis of pressure distribution modeling in vacuum chambers of any arbitrary geometry and also on cross sections calculation for a recharge of ions in exchange reactions by electrons with molecules of re-sidual gas in a wide range of energies and masses of ions being accelerated. The outcomes of model-ing have provided the determination of main parameters and technical requirements for the vacuum system of the DC-60 cyclotron designed for the heavy ion and proton accelerator complex of the University in Astana of the Republic of Kazakhstan

30


WS-18-MoM-OR.1 MASS SPECTOMETRIC ANALYSIS OF COMPLEX GAS MIXTURES BY USING A CRYOGENIC TRAP: APPLICATION TO H2:CH4:N2 PLAS-MAS. Jose A. Ferreira and Francisco L. Tabarés. Laboratorio Nacional de Fusión por Confi-namiento Magnético, CIEMAT, Avda Complutense 22, Madrid The interpretation of mass spectra from gas mixtures showing strong overlapping of the cracking contributions from their constituents has been always challenging, and it is particularly problematic in carbon film deposition plasmas, with strong contribution from several kinds of hydrocarbons. In the present work we describe the use of a cryogenic trap, suitable for thermal desorption studies above liquid nitrogen temperatures, for the discrimination of species with overlapping cracking pat-terns. The cryogenic trap is a simplified model of that described by C. Leitao et al. [1]. A DC glow discharge with a total pressure of 10 mtorr was produced in a mixture of H2:CH4:N2 with 80, 10 and 10 percent respectively. These types of plasmas are of particular interest in fusion research in rela-tion to a new technique being developed for the mitigation of tritium trapping by codeposition in the next step fusion reactor [2]. The complex reactions present in the plasma lead to the formation of numerous stable species that are difficult to identify by mass spectrometry alone. Thus, for example, the presence of N2 and CH4 prevents the use of 28, 29, 16, 15 mass peaks in the deconvolution of the spectra. Some volatile compounds like acetylene, hydrogen cyanide, ethylene etc. [2] are produced in this kind of glow, conveying important information about the reactive processes taking place in the plasma. However, their cracking peaks are strongly masked by the main plasma species. Many of these compounds can be readily condensed at the liquid nitrogen temperature, 78 K. Once exposed to the plasma products, the cryogenic sample can be ramp-heated to desorb the volatile species, there-fore obtaining different mass peaks that evolve with the temperature ramp depending on the dew point of the different species. The obtained data are then compared to previous studies in this type of mixtures. [1] Carlos M.M. Leitao et al. Vacuum, Vol 52 (1999) 23-26 [2] F. L. Tabarés, V. Rohde et al. Plasma Phys. Control. Fusion, Vol 46 (2004) B381-B395

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WS-18-MoM.INV.1 STANDARS AND CALIBRATIONS IN VACUUM TECHNOL-OGY. Karl Jousten, Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Ger-many. The measurement and control of vacuum is an important condition for many industrial processes, e.g. for the coating of glasses, of DVDs und CDs, as well as the production of hard disks, memory chips and processors for computers. In the future it may be even possible that extreme ultraviolet light (EUV) is used for lithography in the semiconductor industry which makes vacuum necessary for the transport of the EUV light. The reflective mirrors will need very good vacuum conditions in order to keep their reflectivity timely stable and to make the whole lithography process a commercial success. For most applications vacuum has turned into a full commodity in the past 20 years, where the buyer has not to care about its functioning. In this scheme, traceable vacuum gauge calibrations and the es-tablishing of standards have become to play an important role. Traceable vacuum gauge calibration means that the reading of a calibrated gauge can be traced to a primary standard for vacuum pressures that ensures highest accuracy and the traceability to the physical units of the SI. Primary standards are operated by the national metrological institutes. In 1999 most of the states of the meter convention signed a mutual recognition arrangement, by which calibration certificates of national metrological institutes are accepted in all these states when some conditions are fulfilled, among them a quality management system as described in the ISO standard 17025. For the further dissemination of the vacuum pressure scale as well as the characterisation of vacuum pump performance, ISO specifications and standards have been developed or are presently under de-velopment. This talk will give a complete overview of the vacuum primary standards, the international system of checking their validity, the scheme of the gauge calibrations down to the end user as well as making notes on the accuracy and reliability of vacuum gauges. The international standardisation work for vacuum technology will be described, also.

28

WS-18 SESSION

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RIVA-TF-MoM-OR.8 STUDY OF THE DC-SPUTTERED Mo ON POLYMER SUB-STRATE FOR FLEXIBLE CIGS SOLAR CELLS M. Andrés and M.T. Gutiérrez. Dep. of En-ergy, CIEMAT. Avda. Complutense, 22. 28040 Madrid SPAIN. For the last few years interest in flexible thin film solar cells has been growing for space power ap-plications, building integration and portable electronic. Thin film Copper Indium Gallium Selenide (CIGS) has been established as a leading contender to these applications. In a recent publication dif-ferent approaches to flexible CIGS thin-film solar cells has been reviewed [1]. There are numerous challenges in developing the technology for manufacturing flexible CIGS, the substitution of the well-established soda-lime-glass substrate by a flexible alternative with drawbacks and without the generation of new obstacles is not a minor problem. The substrate requirements for flexible CIGS so-lar cells are related with a high thermal stability, a sufficient film adhesion and an adequate surface morphology. Molybdenum (Mo) has been used almost exclusively as a back contact material for CIGS-based photovoltaics. Key requirements of the Mo-coated polyimide films for photovoltaic applications are a high electrical conductivity, ohmic contact to CIGS, and high temperature stability in the presence of selenium during CIGS absorber deposition. The aim of the work has been to prepare Mo-coated glass and polyimide and to evaluate their per-formance as flexible back contact for CIGS solar cells. The intrinsic stress, orientation, adhesion, microstructure, reflectance and electrical resistance of dc-sputtered Mo films on glass and polymer substrates has been studied as a function of deposition parameters. Following Thorton and Hoffman [2-4], who comprehensively studies stress in sputtered metallic coatings, we have investigated the effect of Ar gas pressure on the internal film stress in magnetron sputtered Mo with particular emphasis on the problems that are encountered when relatively high melting point Mo coatings, with low thermal expansion coefficient , are deposited on polyimide sub-strates having relatively high thermal expansion coefficient. Substrate expansion due to heating dur-ing deposition places a tensile stress on the coating which is sufficiently large to cause cracking. This difficulty is overcome most effectively by depositing the coating under conditions that build a com-pressive intrinsic stress into the coating. [1] F. Kessler , D. Hermann and M. Powalla, Thin Solid Films 480-481 (2005) 491 [2] J.W. Hoffman, J. Vac. Sci. Technol. A 12(4) (1994), 953 [3] J.A. Thorton and D. W. Hoffman, Thin Solid Films, 171(1989) 5 [4] D. W. Hoffman and J.A. Thorton, J. Vac.Sci. Technol. 20 (1982) 355

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RIVA-TF-MoM-OR.7 INFLUENCE OF THE YTTRIUM CONTENT ON THE ME-CHANICAL PROPERTIES OF Y2O3-ZrO2 THIN FILMS PREPARED BY EB – PVD. I. M. Ochando. Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas. Cantoblanco, 28049 – Madrid, Spain. D. Cáceres. Departamento de Física, Universidad Carlos III de Madrid, E-28911 Leganés, Spain. F. J. García-López. Centro Nacional de Aceleradores, Parque Tecnológico Cartuja’93, 41092 – Sevilla, Spain. R. Escobar-Galindo, R. J. Jiménez-Rioboó and C. Prieto. Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas. Cantoblanco, 28049 – Madrid, Spain. Zirconium oxide is a widely used material because of its heat resistance, low thermal conductivity, high refractive index and high transparency in the visible and near infrared region, very high chemi-cal inertness and high laser damage threshold. Due to these properties, its applications can be found in very different aspects of technology. For instance, zirconia has been applied as thermal barrier coating (TBC)], optical filters, laser mirrors], oxygen sensors], and solid oxide fuel cells]. TBC’s based on yttria stabilized zirconia (YSZ) films prepared by electron beam physical vapour deposition (EB-PVD) are candidates for advanced thermal barrier coatings for the new generation of land-based gas turbines because of the different obtained microstructure respect to other deposition techniques. The low thermal conductivity magnitude for the films is mainly due to two factors: the film microstructure and the intrinsic thermal conductivity value. For YSZ system, this second factor is related with the oxygen defect structure which is induced when Zr4+ ions are substituted with triva-lent Y3+ ions giving rise to oxygen vacancies to compensate electrical charge. Undoubtedly, mechanical properties are of significant importance for TBC and optical applications. In this work, we present a nanoindentation characterization, where hardness and Young modulus have been obtained for a set of (Y2O3)x-(ZrO2)1-x thin films prepared by EB-PVD on Si(100) sub-strates, in order to study the hardness dependence on the yttria content.

25


RIVA-TF-MoM-OR.6 A MINIMALIST SURFACE DECOMPOSITION METHOD AP-PLIED TO STUDY THE SURFACE CONTROL OF THE Au POLYCRYSTALLINE CO-LUMNAR FILM GROWTH. E. Rodríguez-Cañas *, and J. L. Sacedón. Instituto de Ciencia de Materiales de Madrid (CSIC), 28049 Cantoblanco, Madrid, Spain. J. A. Aznárez. Instituto de Física Aplicada (CSIC), Serrano 144, 28006 Madrid, Spain. A. I. Oliva. Cinvestav del IPN Unidad Mérida, Dpto. de Física Aplicada, AP 73- Cordemex 97310 Mérida, Yucatán, Mexico

A method based in the minimalist decomposition of surface morphologies is proposed for the study of surface protrusion terminated growth fronts. The method is applied to the STM morphology im-ages of Au films thermally evaporated on native SiOx/Si(100) for a wide range of Au thickness (60-1800 nm). In this case the bulk film morphology corresponds to a columnar competitive growth, and the growth front is composed of assembled paraboloidal meridian zones. The application of the method allows the numerical synthesis of height distribution curves by the convolution of the statis-tical parameters of the minimalist components. A complete set of statistical parameters, mean values and fluctuations, and their scaling during the growth are obtained. The slope at the borders of paraboloidal meridian zones are maintained near constant during the growth and appears as the con-trolling growth parameter. In fact its high value and the slope distribution curves can be explained by an out of equilibrium growth, controlled by steering and interface phenomena at border of the ter-races in addition of an effective Ehrlich-Schwoebel step-edge barrier. The scaling agrees with simu-lations in which similar selected slopes are considered. One of the minimalist parameters is the fluc-tuation of the columnar height at the film surface, allowing to establish its relation with the other sur-face roughness parameters

24


RIVA-TF.MoM-OR.5 LOW TEMPERATURE DEPOSITION OF TIB2 ON X40 CRMOV 5 1 STEEL SUBSTRATE BY DC MAGNETRON SPUTTERING. A. Duarte1,2*, B. Coelho2, M. Vila2, A.J.S. Fernandes3, F. Oliveira2, F.M. Costa3 R.F. Silva2. 1 - Laboratório - F. Ra-mada, Aços e Industrias, S.A., Apartado 10, 3880-909 Ovar, Portugal. e-mail: [email protected] 2 - CICECO - Dept. of Ceramics & Glass Engineering, University of Avei-ro, 3810-193 Aveiro- Portugal 3 - Dept. of Physics, University of Aveiro, 3810-193 Aveiro- Portugal Titanium diboride (TiB2) films are being investigated due to their promising uses not only in elec-tronic devices but also for mechanical purposes. Its excellent corrosion resistance and chemical sta-bility, as well as high hardness and wear resistance makes TiB2 particularly suitable for aluminium processing (e.g. extrusion, die-casting and machining). The major concern about protective coatings is lack of adhesion to the substrate arising from the high residual stresses developed during film deposition. In the present work TiB2 coatings were produced by non-reactive magnetron sputtering from a TiB2 target on Orvar Supreme tool steel substrate (also know as AISI H13 premium or X40 CrMoV 5 1). Two different substrate types were used, similar to those frequently found on the aluminium injec-tion industry: quenched and tempered/nitrided. The deposition parameters, namely the tar-get/substrate distance, emission and bias currents, were varied in order to obtain adhered and well structured films, suiting the substrates composition and microstructure. The coatings were character-ized by X-Ray diffraction, Scanning electron microscopy/EDS, Scratch test and AFM. The results obtained show that TiB2 can be grown on the steel substrate at low temperature with high deposition rate keeping some crystallinity degree. Depending on the experimental parameters it is possible to coat hot work tool steel with adherent TiB2 thin films by DC sputtering. *corresponding author

23


RIVA-TF-MoM-OR.4 Ta2O5 THIN FILMS PREPARED BY EVAPORATION AND IBAD METHODS: CHARACTERIZATION AND WETTING BEHAVIOUR UNDER UV IRRADIATION. V. Rico, J.P. Espinós, F. Yubero, F. Frutos*, A.R. González-Elipe. Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla). Avda. Américo Vespucio s/n. 41092 Sevilla (Spain). *Dpto. Física Aplicada I, ETS Ingeniería Informática. Avda. Reina Mercedes s/n. 41012 Sevilla (Spain) Ta2O5 thin films have been prepared by evaporation from a tantalum oxide precursor and by assisting the growth of the films by oxygen and nitrogen ion bombardment (IBAD). The obtained thin films depict different microstructures and optical and dielectric properties. In general, the films prepared by evaporation have lower refraction indices that those prepared by IBAD. In this case a clear corre-lation exists between the ion current and energy and the properties of the films. The trend of dielec-tric properties of these thin films agrees with that defined by their optical properties. They also agree with the microstructrue of the films as determined by SEM. A particular type of films was found when prepared by evaporation under grazing conditions. These films depict a columnar microstruc-ture with oblique columns and an extremely high porosity. Refraction indices ranging from 1.7 to 1.2 have been obtained for these thin films. Another interesting property of these thin films refers to its wetting behaviour under UV light. In lit-erature there are many papers dealing with the conversion of the TiO2 surface from partially hydro-phobic into fully hydrophilic by UV irradiation. In this work we also show that Ta2O5 thin films pre-sent a similar behaviour changing from hydrophobic into hydrophilic by illumination. A careful study of this type of transformation is being carried out as a function of the microstructural and struc-tural properties of the films. Doping of Ta2O5 thin films with foreign cations and with nitrogen has revealed to be an effective way to induce a partial change in wetting angle by using visible light for the illumination.

22


RIV-TF-MoM-OR.3 EPITAXIAL MATCHING OF SMALL METALLIC NANO-CLUSTERS IN LARGE-MISFIT SYSTEMS. J.C. Jiménez-Sáez. Departamento de Física y Química Aplicadas a la Técnica Aeronáutica, E.U.I.T. Aeronáutica, Universidad Politécnica de Ma-drid (UPM), E-28040 Madrid, Spain. E-mail: [email protected]. A.M.C. Pérez-Martín and J.J. Jiménez-Rodríguez. Departamento de Electricidad y Electrónica, Facultad de Ciencias Físicas, Uni-versidad Complutense, E-28040 Madrid, Spain. The deposition at low energies of Cu and Au nanoclusters on the Au(001) and Cu(001) substrates re-spectively is studied by constant temperature molecular-dynamics simulations. Clusters have icosa-hedral or Wulff symmetries. Their number of atoms ranges between 13 and 1289. Atomic interac-tions are mimicked by a many-body potential based on the tight-binding model. Deposition energy is of the order of meV/atom and the temperature was 300 K. We have investigated the equilibrium structure of deposited metallic clusters. The influence of the cluster size and of its shape in the low-energy limit on the epitaxial matching has been analyzed. We have taken into account the large lat-tice misfit between the cluster and the substrate (12.8% for Cu/Au(001) and 11.35% for Au/Cu(001)). Previous results show that in cases without misfit the epitaxial growth depends on the size of the clusters and on the temperature as well. Besides in previous works, we have found a dif-ferent elastic behaviour in large clusters when deposition energy is lower or higher than 30 meV/atom. These differences can also induce variations in the epitaxial alignment between cluster and substrate. The possible matching between both structures has been studied by the common neighbour analysis, CNA, which classifies the types of bond; by both the structure factor and an epi-taxy factor which asses the degree of adaptation of both lattices; and finally, by a grain analysis which allows to find out if the deposited-cluster lattice imitates the substrate lattice. Structural prop-erties of the interface (coherent, semicoherent or incoherent), in addition to the bond distances as a function of the distance to the interface have been also investigated.

21


RIVA-TF-MoM-OR.2 STRAIN ANALYSIS OF PHOTOCATALYTIC TiO2 THIN FILMS ON POLYMER SUBSTRATES. C.J. Tavares1, S.M. Marques1, V. Teixeira1, J.O. Car-neiro1, A.J. Fernandes2, E. Alves3, A.R. Ramos3. 1Departamento de Física, Universidade do Minho, 4800-058 Guimarães, Portugal. 2Departamento de Física, Universidade de Aveiro, 3810-193 Aveiro, Portugal. 3Instituto Tecnológico e Nuclear, EN 10, 2686-953 Sacavém, Portugal. [email protected] Titanium dioxide (titania) is a well known photocatalyst used in the semiconductor industry due its efficiency in dissociating pollutant organic compounds. Enhancing the photocatalytic efficiency of this material has become a major concern for the authors, bearing in mind industrial applications for general purpose plastics. On an industrial environment, handling of these films often may cause deg-radation of the coating, hence the vital importance of also enhancing the mechanical properties. TiO2 thin films have been deposited by unbalanced reactive magnetron sputtering from a high purity Ti target in an Ar/O2 atmosphere, at room temperature, on polymer sheets. X-ray diffraction experi-ments revealed for a wide range of deposition parameters that the as-deposited titania thin films are amorphous. The photocatalytic behaviour of the titania coatings was determined by combined ultra-violet irradiation and absorption measurements. The observed photo-decomposition of the aqueous solution (organic pollutant) was measured in the UV/Vis spectrum by the decrease of the maximum absorbance with irradiation time. Analysis of the absorption data allowed us to obtain the decrease in concentration as a function of time to be observed. In order to assess the mechanical behaviour of the as-sputtered films, the film/substrate composite system was loaded unidirectionally using a tensile testing machine. As the system is stretched, cracks transverse to the loading direction developed in the film. The number of cracks increased as the applied strain increased, and the relation between the measured crack density and the applied strain has been used to characterize the film strength and re-late it with the film photocatalytic efficiency.

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RIVA-TF-MoM-OR.1 DETERMINATION OF THE HYDROGEN CONTENT IN DIAMOND-LIKE CARBON AND POLYMERIC THIN FILMS BY REFLECTION ELEC-TRON ENERGY LOSS SPECTROSCOPY. J. Rico, F. Yubero, J.P. Espinós, J. Cotrino, and A.R. González-Elipe. ICMSE (CSIC-USE) Amério Vespucio s/n, E-41092 Sevilla, Spain D. Garg. Air Products and Chemicals, Inc. 7201 Hamilton Boulevard, Allentown, PA 18195-1501, USA A new non-destructive method to determine hydrogen content in diamond-like carbon and polymeric thin film materials is developed. The method relies on quantification of the intensity of elastic peak stemming from the backscattering of electrons with the hydrogen atoms present in the samples as measured by reflection electron energy loss spectroscopy. Quantitative analysis of the hydrogen content at the surface of diamond like carbon thin films is achieved by using phenomenological sen-sitivity factors of hydrogen against the other atoms with reference to polymeric samples. The valid-ity of the method is checked with elastic recoil detection measurements. A comparison is also made with data provided by infrared spectroscopy analysis of the same samples. We estimate that the error bar in the determination of hydrogen content in the samples is around 20% of the total hydrogen content.

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RIVA-TF-MoM-INV.1THIN FILM STACKS FOR SPINTRONIC DEVICES: PREPARATION AND CHARACTERIZATION, P.P.Freitas, S.Freitas and R.Ferreira. INESC MN, Lisbon, Portu-gal and Physics Department, Instituto Superior Tecnico, Lisbon, Portugal Physical Vapour Deposition (PVD) and Ion Beam Deposition (IBD) tools are described as used for the preparation of spintronic device stacks ( hard disk read heads-spin valve and tunnel junction, MRAMS, sensor stacks). These tools allow the uniform deposition of multilayered stacks over 8” wa-fers, where each individual layer has thickneses down to 1nm. The formation of nm thick AlOx and MgO barriers, critical to the formation of state of the art tunnel barriers is revised. For device pattern-ing, both ion-milling and reactive ion etching techniques are used, the latter becoming necessary for device features below 100nm. The complexity of the magnetic stacks poses several challenges for re-active etching techniques. Finally, spintronic device examples will be given, starting with magnetictunel junction read heads for magnetic data storage at densities beyond 100Gbit/in2, followed by MRAMS, and different types of field sensors for position, current, and biomedical imaging applica-tions.

18

RIVA-TF SESSION

17


ETCHC-MoM-OR.8 BORON IMPLANTATION EFFECTS IN CdDS THIN FILMS GROWN BY CHEMICAL SYNTHESIS. K. L. Narayanan, M. Yamaguchi, Toyota Technologi-cal Institute, 2-12 Hisakata, Tempaku, Nagoya-468 8511, Japan.. R. Lozada-Morales1, O. Portillo-Moreno2. Benemérita Universidad Autónoma de Puebla. 1Departmento de Optoelectrónica, Facultad de Ciencias Físico-Matemáticas. 2Facultad de Ciencias Químicas. Puebla, México.O. Zelaya-Angel. Departamento de Física. Centro de Investigación y de Estudios Avanzados del IPN. P.O.Box 14-740, México 07360 D.F. We prepared CdS thin films on ITO/glass substrates using a chemical bath, which were boron-implanted employing 200 keV beams doses of B + ions in the range 1.0 x 1015 – 1.0 x 1016 ions/cm2. The B-doping was successfully carried out, as was proved by the excess of carrier density introduced in the range 0.8 x 1018 – 5.4 x 1018 cm-3, which was calculated from thermopower measurements that we made. The Raman spectroscopy results support the assumption that doubly ionized B+(B3+) enter into the CdS lattice occupying Cd2+ sites, which create shallow donor levels in the forbidden energy band gap, in a similar way that it happens with In3+ ions in CdS.

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ETCHC-MoM-OR.7 TUNGSTEN OXIDE WITH DIFERENT OXYGEN CON-TENT: SLIDING PROPERTIES. T. Polcar, N.M.G. Parreira and A. Cavaleiro a* ICEMS – Grupo de Materiais e Engenharia de Superfícies, Faculdade de Ciências e Tecnologia da Universidade de Coimbra – Pólo II, 3030-201 Coimbra, Portugal. * To whom all correspondence should be addressed ([email protected])

Tungsten oxides were studied in the past due to their electro-optical properties (e.g. exhibit electro-chromic behaviour) and, more recently, due to their applications in gas sensor devices. These studies were particularly focus on the stoichiometric compound WO3 or WO3-x (x = 0–1) prepared by differ-ent method. However, it is difficult to prepare tungsten oxide with low oxygen content by equilib-rium process, since the solubility of oxygen in tungsten in such conditions is very low. Therefore, the non-equilibrium processes must be used being reactive sputtering the most versatile. The sliding properties of tungsten oxide coatings are not well known. Tungsten trioxide studied by Lugscheider et al. showed good tribological properties. It is supposed, that sub-stoichiometric tung-sten trioxide can act as a solid lubricant due to presence of the so-called “Magneli” phases. These phases exhibit a wide range of structures, which leads to the crystallographic shear planes with re-duced binding strength. In this study, we prepared tungsten oxide by reactive magnetron sputtering with oxygen contents of 13 and 75 at.%. Detailed analyses of the XRD patterns of the former W–O coating showed the b.c.c. α-W phase. However, the position of the diffraction peak moved to the lower diffraction angles compared to α-W phase of pure tungsten. This means that oxygen is allocated at the interstitial posi-tions in the lattice, which leads to higher lattice parameters and induces compressive residual stress. Concerning the W25O75 coating, the diffraction peaks of XRD pattern suggest a nanocrystalline structure. At the moment, it is difficult to state that it corresponds to the WO3 monoclinic (the equi-librium structure), since the ICDD patterns ofW20O58, W5O14, WO2.90, and others forms of WO3 (cu-bic, orthorhombic, triclinic) also have diffraction peaks in the same region as the WO3 monoclinic phase. The hardness and Young’s modulus were evaluated by depth sensing indentation. W87O13 and W25O75 coatings exhibited hardness of 26 GPa (similar to that of pure tungsten) and 7 GPa, respec-tively. The coatings displayed a relatively low adhesion (critical load Lc<15 N) to the steel substrate. The tribological measurements were carried out on a pin-on-disc tribometer at room temperature, with a load of 5N and ceramic Si3N4 and Al2O3 balls as sliding partners. The friction coefficient was rather high in case of W87O13 reaching values in range 0.7 - 0.75 for both counterpart materials, and slightly lower for W25O75 (~0.50). The wear rate exhibited a similar trend being higher for the coat-ing with low oxygen content. It can be explained by the presence of a third-body layer between the two surfaces in contact, which decreases friction and protects the coating surface. The third-body consisted of fully oxidized material for both coatings; however, it was much thicker and homogene-ous in the case of W25O75.

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ETCHC-MoM-OR.6 SPUTTERING OF NITRIDES BY LOW-ENERGY IONS OF DIFFERENT MASSES . S.S. Elovikov, A.S. Mosunov, J. C. Colligon*, Yu.A.Ryzhov, I.I.Shkarban, V.E.Yurasova, E.Yu.Zykova. Physics Faculty, Moscow State University, Moscow, 119899, Russia. *Manchester Metropolitan University. John Dalton Extension. Manchester M1 5GD, England, UK

The results of calculations of mass dependence of sputtering yields for nitrides with various ratios between masses of their components, i.e. BN, AlN, and GaN, are presented. The effect of masses of bombarding ions with energy from 200 to 2000 eV on sputtering yields, mean energies and energy spectra of sputtered particles, depths of sputtering origin and number of generations of emitted atoms for nitrides was investigated and discussed. Study of sputtering of these nitrides is of interest both for physics of interaction between atomic par-ticles and solids and from practical viewpoints. BN is an important constructional material due to a set of useful physical and chemical properties: high hardness and electric strength, good heat conduc-tion, thermal and chemical stability. AlN is known for strength, elasticity, good heat conduction, and dielectric strength, and is used in acoustic devices and as a coating in spacecraft components. GaN is used in light-emitting diodes and other electronic devices. In many of applications, surfaces of ni-trides are subject to various kinds of irradiation, which often leads to degradation of their properties. Therefore, it is important to know the resistance of these nitrides to the low-energy ion irradiation. We have used the MD simulation with a mobile single-crystal block of atoms. Polycrystal was simu-lated by rotation of single-crystal block through arbitrary angles for every impinging ion. Inelastic loses were taken into account. Thermal vibrations were considered as uncorrelated. Equations of mo-tion were integrated using predictor-corrector modified scheme. The interaction potential: U(r)=abm(1+ab/r)exp(-r/b),where abm = 52(Z1Z2)3/4, ab = (Z1Z2)1/4/52, b = 0.219Å, Z1 and Z2 are the atomic numbers of the impinging ion and the target atom, respectively. Binding energy Eb of surface atoms was estimated from value of cohesion energy per a bond between atoms in compounds and was corrected using the experimental results. Eb value, thus selected, is: 8.1, 6.8, and 5.4 eV for BN, AlN, and GaN, respectively. It was shown that the sputtering yields Y of BN, AlN, and GaN as functions of mass m1 of normally incident low-energy ions have a nonmonotonic character with a maximum for small m1. For targets with medium mass of atoms (AlN, GaN), the Y(m1) maximum is observed at m2/m1 = 2 (where m2 is the mean atomic mass for compound). In the case of the light-target sputtering (BN), the Y(m1) maximum is at m2/m1 = 1. With increasing E0, the Y(m1) maximum is shifted towards heavier masses and then disappears. Mean energies Ē1 of particles sputtered by low-energy ions from AlN and GaN depend non-monotonically on m1 with a maximum at the same values of m1 as for Y(m1). In BN, Ē1 has maximum for the lightest ions. Energy spectra of a light component of nitrides, which give the main input to sputtering, differ quali-tatively for sputtering by low-energy ions of large and small masses. In the last case, the spectra have longer high-energy tail and broader maximum of distribution that indicates more favorable condi-tions of particle emission with higher energy. Depths of origin x0 of sputtered atoms for GaN and AlN increase with decreasing m1, particularly sharp for small m1. For greater ion masses, at E0 = 200 eV, the curves x0(m1) reach a constant value at x0 ∼ 4 Å for AlN and GaN and slowly grow with m1 for BN. Distribution of the sputtering yield over the number of generations of emitted atoms differs signifi-cantly for targets with light and with heavy masses of atoms. So, for BN, these are the tertiary recoils that give the major contribution to sputtering. In the case of AlN and GaN, the sputtered atoms be-long to primary recoils at lower E0 and to secondary recoils at higher E0. A special feature of nitride sputtering is that the Y(m1) curves reach saturation for lower values of E0 than in the case of equivalent single-element target, with atomic mass equal to the mean of the masses of the two components of the binary compound. This early saturation is caused by the pres-ence of the lighter component (i.e. N) in nitrides.

We would like to thank the Russian Foundation for Basic Research (grants 05-02-17227 and 05-02-17870), and INTAS (grant 03-53-5607) for their support.

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ETCHC-MoM-INV.1 NANOCOMPOSITE HARD COATINGS AS INTERFACE DO-MINATED MATERIALS. Jörg Patscheider, EMPA, Materials Science and Technology. Über-landstr. 129. CH-8600 Dübendorf, Switzerland. e-mail: [email protected] The introduction of ternary metal nitrides, leading to the coating materials with highly improved properties, also brought about the discovery of nanocomposite coatings with increased hardness. Such nanostructured coatings proved successful in promoting hardness, oxidation resistance, im-proved wear behavior and other properties relevant for protective coatings. Examples for these mate-rials are TiN/Si3N4 and TiC/a-C:H. Most nanocomposite hard coatings with well-separated phases show typically a maximum of the hardness, which can range from 30 GPa to reported values exceed-ing 60 GPa, as the composition is changed from the pure polycrystalline phase (no amorphous com-ponent) to compositions dominated by the amorphous phase. At the hardness maximum the domain size of the nanocrystalline phase is below 10 nm and the average thickness of the amorphous layer separating the nanocrystals, amounts to only one to two atomic bond lengths. The grain size at hard-ness maximum for nanocomposites is the same as the single layer thickness in nanomultilayers at the hardness maximum, suggesting similar hardening mechanisms in the two materials classes. contrast to multilayers with its sequential deposition of individual layers, nanocomposites are prepared by codeposition of the involved phases by ion-assisted processes such as unbalanced magnetron PVD, arc-PVD and PACVD. The quality of the amorphous phase in terms of structural perfection and thickness is of decisive influence for the performance of the coatings. ). It can be shown that the chemical nature of the interfaces in TiN/SiNx, despite their inertness, governs the hardness. In some cases the amorphous phase can act as diffusion barrier (Si3N4) for improved thermal stability or as a solid lubricant (a-C or a-C:H). The amorphous phases in nanocomposites thus cause, apart from the enhanced hardness, additional effects that are beneficial for their performance.

13


ETCHC-MoM-OR.5 OES TIME-RESOLVED CHARACTERIZATION OF THE DEPOSITION OF MULTILAYERED COATINGS. J. Romero, A. Lousa. Departamento de Física Aplicada y Optica, Universidad de Barcelona, Avda. Diagonal 647, E-08028 Barcelona, Cata-lunya, Spain. Multilayered structures with nanometric period and manocomposites materials are probably the most promising alternatives to improve the properties of conventional coatings used for mechanical appli-cations. Multilayered structures are generally formed by alternatively piling two materials in a peri-odic sequence ABABAB….., with a period Λ. Most of the multilayered structures referred in the lit-erature present mechanical properties that surpass those of their individual materials: increase of hardness, elastic limit and toughness, and reduction of internal stresses. We have developed a process for the deposition of multilayered structures by r.f. magnetron sputter-ing in a continuous process. A single cathode with a metallic target (Cr) is used, and the alternate deposition of two materials is achieved by periodically alternating the working gas composition. In this way, the deposition of metal/nitride, metal/carbide and nitride/carbide multilayers can be achieved just switching the gas composition between pure Ar and an Ar+N2, pure Ar and an Ar+CH4, and Ar+N2 mixture and Ar+CH4 respectively. Cr/CrN multilayered coatings with bilayer periods (Λ) between 120 and 2 nm were deposited by r.f. magnetron sputtering (13.56 MHz) on Si wafers. The coatings were deposited by reactive sputtering from a 3-in. diameter pure Cr target (99.99% purity) with a r.f. input power of 100 W and a target-substrate distance of 5 cm. Two independent mass-flow meters controlled each gas flux (Ar and N2) during deposition. Chromium thin films were deposited at 1.0 Pa pure Ar pressure, while chromium nitride films were produced in Ar–N2 reactive mixtures where the total working pressure was 1.2 Pa and the nitrogen partial pressure was 0.2 Pa. The Cr/CrN multilayers were deposited alternating both experimental conditions. Cr and CrN growth rates were 0.8 and 0.6 μm/h, respectively; slow enough to be able to produce multilayers in the nanometric range Two nitrogen-related optical signals from plasma de excitation (N2

0 = 337.1 nm and N2+ = 391.4 nm,

were found to be the most easily monitored to appreciate changes in N2 chamber presence. These two well-defined nitrogen optical emission lines were measured in a time-resolved way during multi-layer deposition in order to monitor nitrogen in chamber residence time responses to the cyclic switches in its flow. Exponential time responses were found for cyclic switches, with relaxation times of 1.1 s for the N2 switch off and 0.9 s for the switch on. These times are less than 4% of the deposition time corre-sponding to a bilayer for bilayer periods down to 6-9 nm. Hence, for the multilayers with bilayer thicknesses higher than 9 nm a well defined multilayer structure is expected, while for values lower than 6 nm an increasing influence of interlayers and materials mixing is more probable to occur. The multilayer structure was confirmed by TEM and LA-XRD measurements for bilayer periods higher than 6 nm, what confirms the in-situ predictions of our OES measurements. The highest hard-ness of the coatings set, 28 GPa, was obtained for the coating with the theoretic thinnest bilayer pe-riod (Λ=2.1 nm). This maximum hardness was more than 100% higher than the expected value from the rule-of-mixtures applied to CrN and Cr coatings In summary, time-resolved OES plasma measurements are a useful tool to monitoring in-situ the formation of well defined multilayer structures in a continuous process, with multilayer periods down to a few nanometres.

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ETCHC.MoM.-OR.4 TRIBO-MECHANICAL PROPERTIES OF CrAlN COATINGS DOPED WITH YTTRIUM AND ZIRCONIUM. M. Brizuela, D. González, A. García-Luis, P. Corengia. Fundación INASMET-Tecnalia, Paseo de Mikeletegi 2, 20009 San Sebastián, Spain The aim of this work is to study the influence of doping with Y and Zr on the mechanical and tri-bological behaviour of CrAlN coatings. CrAlN coatings doped with Y and Zr were prepared on high-speed steel (AISI M2) and Si (100) sub-strates by d.c. magnetron sputtering using a commercial equipment (CemeCon® CC800/8) provided of four targets, two of chromium, one of aluminium, and one of the doping material (yttrium or zir-conium) in a mixture of argon and nitrogen. The influence of different deposition parameters (e.g.: Ar/N2 ratio, temperature, doping target power,) on the chemical, mechanical and tribological proper-ties was analysed. The mechanical properties of the films was evaluated with a Fischerscope H100 dynamic microprobe apparatus using a conventional Vickers indenter at loads up to a maximum of 10 mN, to minimise the influence of the underlying base material. Adhesion testing was carried out with a conventional VTT scratch test on films deposited on polished M2 steel samples. Critical loads for adhesion were calculated by optical observation at the first cohesive or adhesive failure of the coating. The friction and wear tests have been performed in a pin-on-disk apparatus against different counterpart materials (AISI 52100 steel and Ti6Al4V alloy). Friction coefficients were continuously recorded during the tests. Wear volume and surface morphology were evaluated on worn areas of coated discs and balls after testing by means of non-contact laser surface profilometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Chemical and microstructural properties have been also investigated by EDS and SEM. The results show great differences when using different doping elements and deposition conditions. The role of the amount and type of doping element has been investigated. Hardness values up to 40 GPa have been found in the case of CrAlN coatings doped with yttrium under certain deposition conditions. The tribological behaviour has also been studied and correlated with the chemical com-position and mechanical properties.

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ETCHC-MoM-OR.3 STUDY OF HYDROGEN AND OXYGEN UPTAKE IN SMART OPTICAL WINDOWS BASED ON YPd AND MgNiPd THIN FILMS BY GDOES. E. Mat-veeva, E.Rayon. Centro MTM, Universidad Politécnica de Valencia, Cami de Vera s/n, E-46022 Valencia Spain. R. Escobar Galindo, J.M. Albella. Departamento Física en Ingeniería de Superficies, Instituto Ciencia de Materiales, Cantoblanco, E-28049 Madrid, Spain. The use of smart optical windows based on YPd and MgNiPd thin coatings on transparent glass, has been extensively studied in the last 15 years due to the possibilities of switching the optical and elec-trical properties in a reversible and controlled way. The key of the switching process is based on the absorption of hydrogen by the reflective metal, converting it to a transparent and semiconductor metal hydride. In our case, the control of the hydration is carried out by an electrochemical process in which the hydrogen ions are absorbed onto the metallic cathode. During the anodic discharge, the hydrogen is released from the metal hydride towards the alkali electrolyte where other reactions may take place (i.e. metal oxidation). These complex processes are localised in-depth the film thickness (approximately 200 nm) and at the interfaces. Incontrollable oxidation of the active films during an-odic discharge depending on the position in the film of the oxide formed can block the hydrogen dif-fusion process and reduce hydrogenation limiting the lifetime of the devices. Therefore, it is crucial to have a detailed knowledge of the mechanisms of hydrogen and oxygen uptake and release in the films. Most of the previous studies has been done by X-ray and infrared characterisation techniques, but they do not provide depth profile information. As an alternative, in this work, we have made use of the high elemental sensitivity and nanometre depth resolution of radiofrequency Glow Discharge Optical Emission Spectroscopy (rf-GDOES) to study the depth profiles of the elements present in the films. In particular, the hydrogen and oxygen uptake and release was followed in samples subjected to different charge and discharge processes. GDOES measurements were performed after each electrochemical experiment (charging and dis-charging), whose kinetics was recorded,. The most representative observations of the GDOES results were: i) The resolution of the layer structure of the film (5 nm Pd/metal layer/glass), ii) the detection and monitoring of hydrogen migration in and out of the film during loading and release cycles and iii) the revelation of the enhanced oxidation of the film after an anodic discharge. The relation of these observations with the performance of the devices will be further discussed in this paper.

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ETCHC-MoM-OR.2 COMPUTER DESIGN OF OPTICAL COATINGS IN SYSTEMS WITH CONTINUOUSLY VARYING REFRACTIVE INDEX. J.F. Trigo. Departamento de Energía, CIEMAT, Avda. Complutense 22, E-28040 Madrid, Spain. I. Preda, S. Palacín, A. Gutiér-rez and L. Soriano. Departamento de Física Aplicada C-XII, Universidad Autónoma de Madrid, Can-toblanco E-28049 Madrid, Spain A simple computerized method for the calculation and refinement of a multilayer discrete optical de-sign has been used to test the accuracy and stability of the given solution with continuously varying refractive index systems as compared with usual high-low (HL) bilayer systems. Motivated for the study of nanostructured mixed materials, which results in a controlled variation of the index of refraction, a code for multilayer Reflectance-Transmittance calculation has been modi-fied to treat the problem of continuously varying refractive index. An example of sinusoidal variation has been studied and compared with discrete HL multilayer to produce a step filter. Also the stability of the filter Transmittance against a random dispersion of the layers thickness has been compared. The conclusion of the comparison was that the bilayered model was better in producing sharp step filters but this performance was rapidly destroyed by a random dispersion up to a 20% of the layers thickness whereas the sinusoidal continuous variation of the refractive index filter remained stable in the same condition. This indicates that the design calculated for these continuous systems would be more easily produced and reproduced in batch industrial processes. On the other hand, the calculation and refinement of the continuous optical coating is much more time consuming with our method so considerable effort has been done to improve the code in this sense.

9


ETCHC--MoM-OR.1 ROOM TEMPERATURE PL CHARACTERIZATION OF MI-CRO- AND NANOCRYSTALLINE DIAMOND GROWN BY MPCVD FROM AR/H2/CH4 MIXTURES M.A. Neto. CICECO Dept. of Ceramics & Glass Engineering, University of Aveiro, Portugal. A.J.S. Fernandes. Dept. of Physics, University of Aveiro, Portugal. R.F. Silva. CICECO- Dept. of Ceramics & Glass Engineering, University of Aveiro, Portugal. F.M. Costa. Dept. of Phys-ics, University of Aveiro, Portugal

Since the first successful efforts to synthesize diamond by chemical vapour deposition (CVD) in the mid-eighties, many technical and scientific improvements have been achieved. Growth rates, quality grade and size up-scaling put CVD diamond into the industrial reality for mechanical and thermal applications, among others. Until recently, most of the available products were based on microcrys-talline CVD diamond (MCD) thick films for brazing or, alternatively, directly coated thin films on tool substrates. Lately, nanocrystalline diamond (NCD) emerged as an alternative to the microcrys-talline material for some applications, mainly due to its enhanced smoothness and electronic proper-ties. Structurally, NCD is composed by small (2-100nm) crystallites frequently surrounded by a non-diamond carbon matrix, resulting in a non-columnar growth. In opposition, MCD crystals grow in a columnar structure according to the Van der Drift model with much lower grain boundary densities.

In this work, a photoluminescence (PL) study at room temperature was accomplished as a comple-ment to well established structural and morphological characterization techniques such as µ-Raman, FTIR, XRD, XPS or SEM. Considering the wide electronic band gap of pure diamond (5.45eV), the near UV excitation (325nm) from an HeCd laser source was selected. The observed NCD and MCD samples were obtained by microwave plasma (MPCVD) from hydrogen poor Ar/H2/CH4 mixtures. A broad violet band dominates the PL spectra of both sample types, evidencing however a stress re-lated wavelength shift between them. The well known 1.681 eV peak related to the Si-vacancy color centre is much more pronounced in the MCD samples, showing that silicon is incorporated in the diamond lattice. In the case of NCD, the absence of the above mentioned peak suggests that Si is probably trapped by the amorphous carbon phases at the grain boundaries. The samples were further structurally and morphologically characterized by micro Raman spectroscopy, XRD and SEM.

8

ETCHC SESSION

7

PARALLEL SESSIONS

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MoM-Pl.1 QUALITY VACUUM MEASUREMENTS FOR PROCESS APPLICATIONS. Charles R. Tilford, Independent Consultant, Gaithersburg, MD USA, [email protected] Vacuum technology is a rapidly maturing field with many industrial applications. This does not mean an end to vacuum science investigations and technical development. However, it does mean an increasing focus on the needs of large-scale processes, whether they are producing energetic par-ticles or consumer products. In addition, more of a focus on quality—fitness for purpose—whether the vacuum contribution is hardware, measurements, or techniques. This process is already under-way—witness the change in vacuum equipment to meet the particular needs of the semiconductor processing industry. But much more needs to be done and the vacuum community will be increas-ingly called upon to apply their expertise outside of their own field of interest. There are many ways of doing this, training courses and documentary standards for example. But there are times when it is most useful for the vacuum specialist to directly collaborate with equipment manufacturers and users of vacuum-technology. Because of the large variety of applications, and different backgrounds of the users, this process can be difficult. But the benefits of such collaborations can be very great, and such collaborations are already quite common in the vacuum equipment area. With the growing complexity of vacuum processes and the importance of measurements for process control, it is prob-able that there will more instances where the specialized knowledge and experience of vacuum measurement specialists will be a welcome addition. Direct participation in problem solving outside of their own field will be a new experience for some vacuum measurement experts. But this is just the latest step in the evolution of vacuum measure-ments and standards. This field started with the need to measure ever-lower pressures. Accuracy, to the extent that it was ever considered, generally was with respect to a local reference—the “magic” reading that produced an acceptable product, or agreement with a “standard” gauge. With the growth of global trade and manufacturing this is no longer acceptable and vacuum measurements must now be established with respect to the internationally accepted measurement system (the SI). A great deal of progress has been made in establishing primary vacuum standards and calibration systems, and ensuring international compatibility. But while proper calibration of an instrument with respect to the SI is necessary, it is not sufficient to ensure that quality measurements are available for the end use. It is also necessary that the calibrated instrument be stable, environmental influences are understood and properly accounted for, the end user is able to properly operate the instrument, and the entire process is affordable. Vacuum measurements are also especially susceptible to appli-cation effects; where the vacuum instrument is located within the process can be critical, as can the mix of gases present. The vacuum specialist cannot resolve all of these issues, but in many cases their participation will be essential if effective solutions are to be devised. This talk will include a broader discussion of these issues, some examples of past efforts of this type, and a discussion of vacuum instrumentation characteristics that should be considered in resolving real world problems. This will include discussion of reference leaks, Spinning Rotor Gages and Re-sidual Gas Analyzers.

5

PLENARY

4

MONDAY MORNING

3

INDEX JUNE 26, 2006 Morning Session ETCHC 9 RIVA-TF 20 WS-18 29 JUNE 26, 2006 Afternoon Session ETCHC 36 RIVA-TF 41 WS-18 50 JUNE 27, 2006 Morning Session JS1: WS-20- RIVA-ETCHC 57 WS-18 66 JUNE 27, 2006 Afternoon Session JS1: WS-20- RIVA-ETCHC 74 WS-18 80 JUNE 28, 2006 Morning Session JS2: WS-20-ETCHC 97 WS-18 105 RIVA-SS 87 JUNE 28, 2006 Afternoon Session Poster Session : RIVA-ETCHC-WS-20 111 Plenary Lecturers Ch. Tilford 6 J. Verhoeven 55 H. Högberg 85

2

Edited by the Asociación Española del Vacío Madrid. Spain

FOREWORD The present book contains de abstracts of plenary lecturers, invited and oral presentations as well as poster presentations. The abstracts have been dis-tributed according to their scheduled presentation of the corresponding ses-sion of the Conference. The abstract correspond to the main parallel activities of: 6TH IBERIAN VACUUM MEETING, RIVA-6 4th EUROPEAN TOPICAL CONFERENCE ON HARD COATINGS, ETCHC-4 WS-18: VACUUM MEASUREMENT, LEAK DETECTION AND CALIBRATION AND VACUUM QUALITY CONTROL WS-20: OPTICAL AND DECORATIVE COATINGS Two join sessions has been scheduled the first one to present aspects of the Thin Films with the workshop devoted to Optical and Decorative Coatings and the second one is related with hard coatings and tribology. Presentations related with vacuum measurements has been organised in a workshop with aspects of the leak detection and vacuum quality control. The Organising Committee and the Editor are grateful to the authors for their contributions, specially the significant contributions of the Portuguese scientific community. We also thank the International Programme Commit-tee for their work in the reviewing of the abstract. A special acknowledge is to Professor Ángela Calvo for her work in preparing of the local arrangement. We also thank the University of Salamanca for all the facilities.

José L. de Segovia Editor

1

Sigilum Universitatis Studii Salamantini

6TH IBERIAN VACUUM MEETING, RIVA-6

12 REUNIÓN ESPAÑOLA DEL VACÍO Y SUS APLICACIONES, REVA-12 REUNIÂO PORTUGUESA DE VÁCUO E SUAS APLICAÇÕES, RIVA-6

4th EUROPEAN TOPICAL CONFERENCE ON HARD COATINGS, ETCHC-4

WS-18: VACUUM MEASUREMENT, LEAK DETECTION AND CALIBRATION AND

QUALITY CONTROL IN ADVANCED INDUSTRIES

WS-20: OPTICAL AND DECORATIVE COATINGS

June 26-30, 2006

Abstract Book EDITORS: José L. de Segovia Instituto de Ciencia de Materiales de Madrid. CSIC. ES O. Teodoro Iniversidade Nova de Lisboa. PT

Documents

Wüest M. 51 Wykes M. 82 Yamaguchi M. 17 Ybarra … de abstracts.pdf144 Cavaleiro A. 16, 39, 79, 96, 102 Chigiatto P. 81 Coelho B. 24 Colera I. 114 Colligon J.S. 15 Contreras-Puente