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8.10.2007 EFUG 2007- Arcachon
FIBs and soft matter... materials…structures…
Marziale Milani
Materials Science Dept. & Laboratorio FIB/SEM “BOMBAY”University Milano-Bicocca, Milano, Italy
8.10.2007 EFUG 2007- Arcachon
Summary
Introduction
Organic Crystals
FIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda, Crustacea)
Post-fabrication processing of Superluminescent Diodes (SLDs)
Dual FIB/SEM systems for plasma facing materials for magnetic thermonuclear fusion
Laser ablation
Results
Caveat
Acknowledgements
8.10.2007 EFUG 2007- Arcachon
What do we mean by soft matter?
1) Complexity 2) Flexibility[P.G. De Gennes – Nobel Lecture 9 December, 1991]• Emergent properties• Order/disorder• Heterogeneous materials and structures• Quantum Phenomena• Nonequilibrium Physics
Where we are going depends on our knowledge, and our knowledgedepends on where we are going…
[Tess Gerritsen – The Surgeon, Ballantine Publish Group 2001]
Tools, samples, questions strategies and researchproblems: solutions and creation
8.10.2007 EFUG 2007- Arcachon
Soft Matter……
HARD MATTER
ColloidalDispersions
LiquidCrystals
Biomatter(proteins, membranes, nucleic acids)
SOFT MATTER
Non-CrystallineSolids
Cristalline Solids (metals, insulators, semiconductors)
cristalline Solidsdefects (point, dislocations, surfaces & interfaces)
Condensed matter systems
AmorphousSolids (glass)
Polymer Solids (glass & rubber)
Quasicrystals
PolymerMelts and Solutions
Coexistent phasesCells,tissues, organsHeterostructuredmaterialsSubmicron sizedmaterials
8.10.2007 EFUG 2007- Arcachon
FIB/SEM is suitable system to investigate soft matter
Imaging with ion- and electron- beam. (ion beam not only as a milling tool)
Soft matter is not always friendly: samples can be... .....insulating, with very rough surfaces, inhomogeneous, and sometimes without additional information.
Strategies to handle all that kind of variety: • use of e-beam for charge neutralization during milling • Low Vacuum for imaging• heavy Pt deposition for surface smoothing • change of milling parameters and of sample orientation to reduce “curtain effects” and for a milling as regular as possible on the trench walls.
8.10.2007 EFUG 2007- Arcachon
Steps and loops in FIB/SEMPrimary beam(s) (and parameters)
Interactions with the sample (surface, subsurface and bulk)
Desired modifications and operations + undesidered modifications(observable and nonobservable)
Not only milling for e-imagingArtifacts
Sample preparation
Secondary particles –output signals
Different detectors (role of relative geometry and scanning operations) Not only imaging
Image reconstructionImage interpretation
Characterization and hypothesis on processes other than those due to primary beams
8.10.2007 EFUG 2007- Arcachon
1-mm Organic Crystals(Rhodamine 590)for Lasers and Non-linear Optics
In literature one can find examples of rhodamine crystals grown from a solution with typical dimensions of less than 5 um.
A larger organic crystals with a linear dimension up to 1 mm have been built by means of a novel preparation protocol with a solution of rhodamine 590 as a starting precursor.
These exceptional large dimensions can pave the way to a direct exploitation of rhodamine crystals, since they might be imbedded inoptoelectronic devices.
Organic Crystals
Some ‘natural polished’ faces are present and they are coplanar to crystal planes.
Edges and ridges of a single crystal point out directions in which the crystal growths after the first nucleation.
Some cracks in the crystal bulk are also evident with a dimension of few tens ofnanometers.
They could not have consequences on optical properties of a such crystal
8.10.2007 EFUG 2007- Arcachon
Organic Crystals
crystal habit fluorescence
one of the three independent N,N’-diethylrhodamine molecules
8.10.2007 EFUG 2007- Arcachon
Ion imaging BSE: morphology and composition
Sectioning
Organic Crystals
Pt deposition
8.10.2007 EFUG 2007- Arcachon
FIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda, Crustacea)
Presence of metals (Cu, Zn, Ga, Ag) and significant peaks of P, S, and Ca.
The spectrum refers to an ensemble of cells ( B- and S- cells).
EDS spectrum of the section.
A critical part of this analysis is section preparation.
It is fundamental in determining the volume of interaction that generates X rays apart location selection and quality of the section.
Same order of magnitude of the granules size and depth of generation of X-rays suggest the usefulness of a sample with a thickness lower than 1 micron.
FIB role in preparing quasi – lamellae in situ appears therefore promising
8.10.2007 EFUG 2007- Arcachon
FIB sectioning for metal detection in digestive gland cells of P. scaber (Isopoda, Crustacea)
P, Zn, Cu EDX
BSE image
S, Zn, Cu EDX
Ga EDX map
8.10.2007 EFUG 2007- Arcachon
Post-fabrication processing of Superluminescent Diodes (SLDs)
• Edge emitting
• High power
• Broad band
Applications:
• Fiber gyroscopes
• Optical Coherence Tomography
• Short haul comms
• Wavelength division multiplexing
Z
X
Y
Device Geometry
Stripe SLD (S-SLD) Tapered SLD (T-SLD)
FIB manipulation:output facet amorphisation
FIB manipulation:Pt stripes deposited on output facet
8.10.2007 EFUG 2007- Arcachon
Facet Amorphisation - Testing
7.5 x 7.5µm² squares FIB millingIon Beam currents: 50 – 500pADwell Times: 1 – 8µs(secondary electrons imaging)
Nano-Patterning - Testing
Patterning - Testing
Ion Beam current: 100pADwell Times: 0.5 – 1µswith 0.5µs DT milled lines obtained – no Ga droplets(secondary electrons imaging)
Light Corrent Characteristics (LI)
Pulsed operation (5µs, 200Hz)
0
20
40
60
80
100
120
140
160
0 500 1000 1500 2000 2500
current (mA)
outp
ut p
ower
(mW
)
LB72 FIBLB67 (as LB72)LB100 FIBLB73 (as LB100)
8.10.2007 EFUG 2007- Arcachon
Dual FIB/SEM systems for plasma facing materials for magnetic thermonuclear fusion
Carbon fibers
Carbon fibers:
a precursor
8.10.2007 EFUG 2007- Arcachon
Laser ablationA set of Al and Si targets are considered for laser ablation.Electron images, ion images and FIB cross sectioning can be investigated for an impact scenario description.
Si
BSE:A+B
BSE:A-B
Ion image
8.10.2007 EFUG 2007- Arcachon
ResultsOrganic Crystalsactive material shaping and optical cavity preparationFIB sectioning for metal detection in digestive gland cells of P.scaber (Isopoda,
Crustacea)there is the presence of Copper and Zinc in the exposed section, no significant presence of
Iron; Copper content changes with respect to zinc content while moving from bright spots (metal granules) towards dark sites; there is the presence of Gallium in the exposed section;expected contamination by Ga ions is of low level, although detectable; quality of the section is good after a sequence of cutting and polishing (obtained by a decreasing ion beam currents), and the planarity can be appreciated by electron imaging
Post-fabrication processing of Superluminescent Diodes (SLDs) device characteristic and performances geometrically controlled modificationsDual FIB/SEM systems for plasma facing materials for magnetic
thermonuclear fusion material stresses identification and electrical properties characterizationLaser ablationcrater morphology and intermediate processes “zoology”
8.10.2007 EFUG 2007- Arcachon
CaveatHoc ipsum cum consideraveris: illud
quoque tibi occurrat velim: ut átenebrarum ratione seiungasumbram.
Non est umbra tenebrae: sed veltenebrarum vestigium in lumine.
Vel luminis vestigium in tenebris. Velparticeps lucis et tenebrae.
Vel compositum ex luce et tenebris. Velmixtum ex luce et tenebris.
Vel neutrum á luce et tenebris, et abutrisque se-iunctum.
Et haec vel indè quia non sit plena lucisveritas, vel quia sit falsa lux.
Vel quia nec vera nec falsa, sed eiusquod veré est aut falsé,vestigium, etc.
Habeatur autem in proposito. ut lucisvestigium, lucis particeps, lux non plena.
Giordano Bruno Giordano Bruno -- IntentioIntentio Secunda Secunda ““De De umbrisumbris idearumidearum”” (1582(1582))
Mirror effect(s)
8.10.2007 EFUG 2007- Arcachon
F. Tatti FEI Italia (I)
D. Drobne Dept. Biology University of Ljubljana (SLO)
C. Savoia STM-Agrate B. (I)
F. Causa Dept. Electronic and Electrical EngineeringUniversity of Bath (UK)
and……….
in cooperation with