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© Fraunhofer IOF
Page 1
Overv iew of ALD-Act iv i t ies f or Opt ical Appl icat ions: M at er ials, Ref ract ive and
Di f f ract ive Opt ics
Adr iana Szeghalm i , 1,2, S. Shestaeva 1, Ast rid Binge l1
L. Ghazaryan 2, K. Pfe iffe r2, S. Ra tzsch 2
2Friedrich Schille r University Jena , Inst itu te of Applied Physics
a .szegha lmi@uni-jena .de
1Fraunhofer Inst itu te for Applied Opt ics and Precision Engineering
Workshop Opt ica l Coa t ings for Laser Applica t ions 2016 - Buchs
© Fraunhofer IOF
Page 2
Out l ine
In t roduct ion
Coat ing equipm ent
Resul t s
Materia ls
In te rfe rence Coat ings
Diffract ive Opt ics
Out look
© Fraunhofer IOF
Page 3
Dr. Adriana Szeghalmi
Prof essional career since f inal degree 10/2015 −to da te Group Manager ALD for Opt ics FhG-IOF Jena 05/2010−to da te Emmy Noether Group Leader FSU Jena 05/2007−04/2010 Postdoc, Max Planck Inst itu te of Microst ructure Physics
(Prof. U. Göse le , Dr. M. Knez) Halle (Saa le ) 04/2005−04/2007 Postdoc, University of Manitoba , Canada
(Prof. K. M. Gough) Winnipeg
Universi t y educat ion 07/2001-02/2005 PhD studies, University of Würzburg (Prof. W. Kiefe r) 04/2000-03/2001 Exchange student a t the University of Würzburg 10/1997-06/2001 Study of Chemist ry and Physics, Babes-Bolya i University,
Romania
© Fraunhofer IOF
Page 4
Li l i t GhazaryanKr ist in Pf ei f f erVivek Belad iyaSvet lana Shest aevaAst r id BingelDavid Käst ner
Alum ni : M . Sc. Haiyue YangDr. Pascal GenevéeM . Sc. Ernest Ahiav iDr . St ephan Rat zsch
ALD Team
© Fraunhofer IOF
Page 5
The ALD Solut ion to Enhance Opt ical Performance
[1]
[1] www.marquard t -kempen.de /s/cc_images/cache_2435481376.jpg?t=1362993658[2] L. Ghazaryan , A. Szegha lmi, E. B. Kley, U. Schulz, DPMA Anmeldung . 2016
1 µm
TiO2
ESA, Sent ine l-2
© Fraunhofer IOF
Page 6
Why ALD?
[1] T. Weber, T. Käsebie r, A. Szegha lmi, M. Knez, E. B. Kley, A. Tünnermann. Nanosca le Research Le t t . 6 (2011) 558[2] A. Szegha lmi e t a l., Applied Physics Le t t e rs, 2009, 94, 133111-1/3.
ALD
conformality
repeatability
low roughness
precise thickness
control
uniformity
Ta2O5 / Al2O3 Nanolaminate(2.3 nm / 6.7 nm) x N
0 50 100 150 200 250 3000
5
10
15
20
25
30
35
40
Al2O
3-Th
ickn
ess
(nm
)
ALD cycles
Ir
[1]
[2]
© Fraunhofer IOF
Page 7
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 8
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 9
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 10
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
Ar purge
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 11
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
Ar purge
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 12
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
Ar purge
Ar purge
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 13
HSi(N(CH3)2)3
O2 Plasma
SiO2 ALD cycle
Ar purge
Ar purge
ALD atomic layer-by-layer coat ing technology
© Fraunhofer IOF
Page 14
Coat ing Equipm ent
Oxford Plasma Technologies (UK)
Open loaded ALD tool
Top-Flow reactor
ICP p lasma
Up to 200 mm diameter wafers (150 mm square)
Height up to 20 mm
Up to 4 precursors (H2O + 3 Meta l Precursors)
Tempera ture range 25°C…200°C
Ellipsomet ry port s, Woollam ellipsometer
ca . 400k€
Insta lled 2011
Oxides
1. OpAL PEALD t oo l
© Fraunhofer IOF
Page 15
Coat ing Equipm ent
Picosun Oy (F)
Load-lock and open loaded ALD
Hot-wall top-flow dual chamber design
RF Plasma
Up to 200 mm diameter wafers (150 mm square)
Height up to 100 mm
Up to 6 precursors (H2O + 5 Meta l Precursors)
Tempera ture range 25°C…500°C
Load-lock in tegra ted in GloveBox
ca . 400k€
Insta lled 2013
Metals and Oxides
2. Sunale R200 PEALD t oo l
© Fraunhofer IOF
Page 16
Larger Reactor Conf igurat ion
In com m ission ing
Diameter 330 mm
Height up to 100 mm
Thermal and Plasma Enhanced ALD
To be insta lled March 2017 @ IOF Jena
© Fraunhofer IOF
Page 17
Out l ine
In t roduct ion
Coat ing equipm ent
Resul t s
Materia ls
In te rfe rence Coat ings
Diffract ive Opt ics
Out look
© Fraunhofer IOF
Page 18
M at er ials
developm ent o f t he t herm al and/ or PEALD processes SiO2, Al2O3, TiO2, HfO2, Ta 2O5
MgF2, CaF2, LaF3
irid ium a lucones & nanoporous Al2O3
composite mate ria ls & nanoporous SiO2
l i t erat ure: Ru, Ag, Au, W, graphene, n i t r ides, SrTiO3, Nb2O5, ZrO2…
opt ical proper t ies m orphology m echanical proper t ies
ℎ𝑐𝑐 =Γ𝐸𝐸𝑓𝑓𝑍𝑍𝜎𝜎2
hc crit ica l coa t ing th icknessEf Elast ic modulus filmΓ fracture resistanceZ geometrical factor (1.976)σ mechanical stress
© Fraunhofer IOF
Page 19
Oxides: Summary of Ref ract ive Index
300 400 500 600 700 800 9001,4
1,6
1,8
2,0
2,2
2,4
2,6
2,8
3,0R
efra
ctiv
e in
dex
Wavelength (nm)
HfO2 100°C SiO2 100°C Al2O3 200°C TiO2 100°C Al2O3:TiO2 120°C
© Fraunhofer IOF
Page 20
TiO2
Titan ium(IV) isopropoxideTi[OCH(CH3)2]4hea ted and bubbled a t 45-60°C
Titan ium(IV) ch lorideTiCl4
+ H2OH2O2O2 Plasma
+ H2O
© Fraunhofer IOF
Page 21
TiO2 Film Grow th
Linear ALD growth with number of cycles Influence of Deposit ion Tempera ture and O2-Plasma
© Fraunhofer IOF
Page 22
PEALD processes provide h igher re fract ive index a t lower tempera ture than the thermal ALD of t it an ia
Tempera ture has lit t le in fluence in PEALD of t it an ia
∆n = ~0.03 ∆n = ~ 0.4
TiO2 Refract ive Index
© Fraunhofer IOF
Page 23
TiO2 Thickness Uniformity
TiO2/Al2O3 PEALD 120°C Ø 150 mm Si wafer: SD 1 σ = 1.07% Homogene ity (Max-Min/2d average) = 2.1%
n @633 nm = 2.4232 ± 0.004
© Fraunhofer IOF
Page 24
TiO2 Tensile Mechanical St ress
σ decreases in nanolamina tes
© Fraunhofer IOF
Page 25
HfO2
Tet rakis(d imethylamino)hafn ium(IV)[(CH3)2N]4Hf
hea ted and bubbled a t 50°C
+ O2 Plasma
© Fraunhofer IOF
Page 26
Opt ical Propert ies – Inf luence of Temperature
high sca t te ring losses above 200°C deposit ion tempera ture
© Fraunhofer IOF
Page 27
Thickness and Refract ive Index Uniformity
HfO2 PEALD 100°C Ø 200 mm Si wafer: SD 1 σ = 2.24% Homogene ity (Max-Min/2d average) = 4.5% Plasma flow from the top
-100 -50 0 50 100-100
-50
0
50
100
Thickness (nm)
Posi
tion
Y (m
m)
Position X (mm)
49,0049,5050,0050,5051,0051,5052,0052,5053,0053,5054,00
-100 -80 -60 -40 -20 0 20 40 60 80 100-100
-80
-60
-40
-20
0
20
40
60
80
100
Refractive index
Posi
tion
Y (m
m)
Position X (mm)
1,8861,8891,8921,8951,8981,9011,9041,9071,909
n = 1.8999 ± 0.0065
© Fraunhofer IOF
Page 28
HfO2 Refract ive Index – PVD & ALD
1,7
1,8
1,9
2,0
2,1
2,2
300°
C20
0°C
IP
XeAr
ALD
PLD
IBS
MS
PIADIAD
n @
400
nm
EBE
100°
CO. Stenze l, S. Wilbrandt , S. Yulin , N. Kaise r, M. Held , A. Tünnermann, J. Biskupek, U. Kaise r, Opt . Mate r. Express 2011, 1, 278.
© Fraunhofer IOF
Page 29
HfO2 TEM image
deposited a t 100°C ca . 5 nm Nanocrysta llit es ca . 3.5 nm HfO2/SiO2 composite layer a t the Si-wafer in te rface
© Fraunhofer IOF
Page 30
HfO2 Tensile Mechanical St ress
σ increases with increasing deposit ion tempera ture due to crysta lliza t ion σ sligh t ly increases with increasing ion energy
100 200 300400
500
600
700
800
900
Bulusu HfO2 -FSU SP LEP HEP
Stre
ss (M
Pa)
Temperature (°C)
© Fraunhofer IOF
Page 31
HfO2 Tensile Mechanical St ress
σ decreases in nanolamina tes (HfO2/SiO2 and HfO2/Al2O3)
1,900
1,925
1,950
1,975
2,000
2,025
2,050 Refractive index
Ref
ract
ive
inde
x
Standard HfO2 homogeneous without needles
NL 15/1.5
NL15/3
NL 7/3
400
450
500
550
600
650
700
Film stress
Film
str
ess
(MPa
)
© Fraunhofer IOF
Page 32
Al2O3
Trimethyla luminum(CH3)3Al
own vapour pressure
+ H2OO2 Plasma
Aluminum chlorideAlCl3
+ H2O
© Fraunhofer IOF
Page 33
100 nm Al2O3 on 200 mm Si w afer
© Fraunhofer IOF
Page 34
Inf luence of Deposit ion Temperature
200 300 400 500 600 700 800 9001,60
1,65
1,70
1,75
1,80
1,85
Ref
ract
ive
inde
x
Wavelength (nm)
Al2O3-200°C thermal Al2O3-120°C thermal
impact on reproducib ility of re fract ive index t empera ture has less in fluence in PEALD processes than in thermal ALD
∆n = 0.015with in measurement accuracy
∆n = 0.025
400 600 800 1000
1,55
1,60
1,65
1,70
1,75 Al2O
3 Plasma ALD 25°C
Ref
ract
ive
inde
x n
Wavelength (nm)
Al2O3 Plasma ALD 120°C Al2O3 Plasma ALD 200°C Al2O3 Plasma ALD 250°C Al2O3 Plasma ALD 300°C
© Fraunhofer IOF
Page 35
Thickness Uniformity
Al2O3 thermal 300°C Ø 200 mm Si wafer: SD 1 σ = 1.1% Homogene ity (Max-Min/2d average) = 2.44%
n = 1.6484 ± 0.0004
-100 -80 -60 -40 -20 0 20 40 60 80 100100
80
60
40
20
0
-20
-40
-60
-80
-100Thickness (nm)
Posi
tion
Y [m
m]
Position X [mm]
100.4100.7101.1101.4101.7102.1102.4102.8103.1103.4103.8104.1104.4104.8105.1105.5
-100 -80 -60 -40 -20 0 20 40 60 80 100100
80
60
40
20
0
-20
-40
-60
-80
-100 Refractive index
Posi
tion
Y [m
m]
Position X [mm]
1.6481.6481.6491.6491.6491.6491.6501.6501.6501.6511.6511.6511.652
© Fraunhofer IOF
Page 36
Opt ical Losses
Al2O3 with low opt ica l losses have been achieved confirmed by lase r ca lorimet ry measurements
@ 1064 nm on 300 nm th ick Al2O3, ca . 2,5 ppm
Thermal PEALD
© Fraunhofer IOF
Page 37
Al2O3 Tensile Mechanical St ress
σ decreases with increasing deposit ion tempera ture PEALD coa t ings show lower mechanica l st ress than thermal ALD a lumina residua l st ress = ∑ (thermal st ress + in t rinsic st ress)
0 50 100 150 200 250 300 350 400 450 5000
100
200
300
400
500
600 Krautheim Tripp Miller Bulusu Ylivaara FSU-Thermal FSU-PEALD
Stre
ss [M
Pa]
Temperature [°C]
© Fraunhofer IOF
Page 38
Al2O3 FTIR Spect ra
3800 3600 3400 3200 3000
0,000
0,002
0,004
0,006
3570
3610 35
70
Abs
orba
nce
(a.u
.)
Wavenumber (cm-1)
Plasma 120°C Thermal 120°C
3800 3600 3400 3200 3000 2800
0,000
0,002
0,004
0,006 3570
Abs
orba
nce
(a.u
.)
Wavenumber (cm-1)
Plasma 120°C Plasma 200°C Plasma 250°C Plasma 300°C
-OH content decreases with increasing tempera ture diffe ren t hydrogen-bonding in thermal vs. PEALD processes
© Fraunhofer IOF
Page 39
SiO2
Tris(d imethylamino)silane[(CH3)2N]3SiH
own vapour pressure
+ O2 Plasma
Bis(d ie thylamino)silane[(C2H5)2N]2SiH2
hea ted and bubbled a t 70°C
© Fraunhofer IOF
Page 40
Inf luence of Subst rate Material
ca libra t ion curves a re required
© Fraunhofer IOF
Page 41
Opt ical Losses
materia ls with low opt ica l losses have been achieved confirmed by lase r ca lorimet ry measurements SiO2 PEALD 200°C example
@ 1064 nm on 300 nm th ick SiO2, ca . 1,5 ppm (Laser Zent rum Hannover)
200 400 600-0,5
0,0
0,5
1,0
Opt
ical
loss
es (%
)
Wavelength (nm)
SiO2 PlasmaSubstrate
© Fraunhofer IOF
Page 42
Thickness Uniformity
SiO2 PEALD 100°C Ø 200 mm Si wafer: SD 1 σ = 1.36% Homogene ity (Max-Min/2d average) = 2.31%
n = 1.4472 ± 0.0005
-100 -50 0 50 100-100
-50
0
50
100
Pos
itio
n Y
(m
m)
Position X (mm)
100,1100,3100,5101,0101,5102,0102,5103,0103,5104,0104,6105,0
Thickness (nm)
-100 -50 0 50 100-100
-50
0
50
100
Pos
itio
n Y
(m
m)
Position X (mm)
Refractive index1,44601,44631,44651,44681,44701,44731,44751,44771,4480
© Fraunhofer IOF
Page 43
Composites and Nanoporous SiO2
a tomica lly mixed Al2O3/SiO2 composites and se lect ive removal of Al2O3
Si Al O
XYN [email protected] nm Al2O3: SiO2
L. Ghazaryan , A. Szegha lmi, E. B. Kley, U. Schulz, DPMA Anmeldung . 2016L. Ghazaryan , A. Szegha lmi, E. B. Kley, DPMA Anmeldung . Anmelde tag 24. Februar 2015. 10 2015 203 307.4
© Fraunhofer IOF
Page 44
Nanoporous SiO2
a tomica lly mixed Al2O3/SiO2 composites and se lect ive removal of Al2O3
precise ly cont ro l porosity and re fract ive index through a tomic composit ion
4:23:2
2:2Before etching
© Fraunhofer IOF
Page 45
Applicat ions of Nanoporous SiO2
ant ire flect ion coa t ings
one layer
double side coa t ing
92 nm each side
n = 1.22
Over 98 % Transmit tance in VIS
Low opt ica l losses
© Fraunhofer IOF
Page 46
Applicat ions of Nanoporous SiO2
diffusion membrane High e fficiency t ransmission gra t ings
ALD Al2O3
Planarisation
Al2O3:SiO2 alloy
100 μm
1 µm
© Fraunhofer IOF
Page 47
Out l ine
In t roduct ion
Coat ing equipm ent
Resul t s
Materia ls
In te rfe rence Coat ings
Diffract ive Opt ics
Out look
© Fraunhofer IOF
Page 48
Ant iref lect ion Coat ing SEM Image
Tot al 391 nm SiO2 97.3 HfO2 29.8 SiO2 19.5 HfO2 153.5 SiO2 10.4 HfO2 40.5 SiO2 19.1 HfO2 18.6 N-SF8 subst ra te
© Fraunhofer IOF
Page 49
Ant iref lect ion Coat ings
[3] K. Pfe iffe r, S. Shestaeva, A. Binge l, P. Munzert , L. Ghazaryan, C. van Helvoirt , W. M. M. Kesse ls, U. Sanli, C. Grévent , G. Schütz, M. Putkonen, I. Buchanan, L. Jensen, D. Ristau , A. Tünnermann, A. Szegha lmi. Opt . Mater. Express 6 (2016) 660[4] A. Szegha lmi, M. Helgert , R. Brunner, F. Heyroth , U. Göse le , M. Knez. Appl. Opt . 48 (2009) 1727
© Fraunhofer IOF
Page 50
Dichroic Mirror at 355 nmTot al deposi t ion t im e: ~4 daysNO opt ical m oni t or ing
30 layers [HfO2(Al2O3) and SiO2] ca . 1.9 µm to ta l th ickness high adhesion coa t ing to subst ra te >99.5% re flectance a t 45° AOI @355
300 400 500 600 700 800 900 1000 11000
20
40
60
80
100Exp. av.-pol.Design av.-pol.
Ref
lect
ance
(%)
Wavelength (nm)
AOI=45°
320 340 360 380 40090919293949596979899
100Exp. av.-pol.Design av.-pol.
Ref
lect
ance
(%)
Wavelength (nm)
AOI=45°
500 550 1000 1050 11000
1
2
3
4
5Exp. av.-pol.Design av.-pol.
Ref
lect
ance
(%)
Wavelength (nm)
AOI=45°
© Fraunhofer IOF
Page 51
Highly Ref lect ive Dichroic Mirror cracking of the coa t ing and subst ra te
© Fraunhofer IOF
Page 52
Highly Ref lect ive Dichroic Mirror
Hf O2
cracking of the coa t ing and subst ra te crack occurs a fte r deposit ion
SiO2
Hf O2
© Fraunhofer IOF
Page 53
Out l ine
In t roduct ion
Coat ing equipm ent
Resul t s
Materia ls
In te rfe rence Coat ings
Diffract ive Opt ics
Out look
© Fraunhofer IOF
Page 54
Resonant Waveguides
A. Szeghalmi, E. B. Kley, M. Knez. J. Phys. Chem. C 114 (2010) 21150A. Szeghalmi, M. Helgert , R. Brunner, F. Heyro th , U. Göse le , M. Knez. Adv. Funct . Mater. 20 (2010) 2053
PC
C-PasteFilm Thickness
~ 120 nm(~2 hours deposit ion)
Narrow Band
481 nm
nanost ructure + ALD coa t ing
© Fraunhofer IOF
Page 55
Ir wire grid polarizer
100 nm
Resist grating
ALD coating
IBE etching Ir
ICP etching resist
ALD coating
sputtering
Polarizers
[1] T. Weber, T. Käseb ie r, A. Szegha lmi, M. Knez, E. B. Kley, A. Tünnermann. Nanosca le Research Le t t . 2011, 6, 558[2] Y. Bourg in , T. Sie fke , T. Käsebie r, P. Genevée , A. Szegha lmi, E. B. Kley, U. D. Ze itner. Opt ics Express, 2015, 23, 16628
© Fraunhofer IOF
Page 56
High Ef f iciency Transmission Grat ings
S. Ra tzsch , E. B. Kley, A. Tünnermann, A. Szegha lmi. Mate ria ls, 2015, 8, 7805-7812.S. Ra tzsch , E. B. Kley, A. Tünnermann, A. Szegha lmi. Opt ics Express, 2015, 23, 17955-17965.S. Ra tzsch , E. B. Kley, A. Tünnermann, A. Szegha lmi. Nanotechnology, 2015, 26, 024003 (1-11).
Wave length (nm)
Diff
ract
ion
Effi
cien
cy (%
)
measured d iffract ion e fficiency (-1 order) gra t ing for TE-Pola risa t ion 97.5% measured d iffract ion e fficiency (-1 order) gra t ing for TM-Polarisa t ion 95%
400 nm
575 nmAl2O3/TiO2
SiO2
© Fraunhofer IOF
Page 57
50nm250nm
FIB cross section
SiO2
TiO2
p=555nm
0,76 0,78 0,80 0,82 0,84 0,86 0,88 0,9085
90
95
100
Effic
ienc
y [%
]
Wavelength [µm]
theory measurement
Δλ = 130nm
High Index Contrast Grat ing
fabrica te a low fill-factor gra t ing in SiO2 conformal overcoa t ing with ALD TiO2 th ickness ca . 44 nm
© Fraunhofer IOF
Page 58
ALD Por t f o l io @ Jena (Fraunhof er IOF & Universi t y)
ALD M at er ial Developm ent
In t er f erence Coat ing Syst em s
Nano and M icrost ruct ured Opt ics
Adriana .Szegha [email protected]
© Fraunhofer IOF
Page 59
Acknow ledgement
Andreas TünnermannErnst Bernhard KleyUwe ZeitnerPe te r MunzertUlrike SchulzNorbert Kaiser
IAP and IOF co l leagues