Overview of ALD -Activities for Optical Applications: …MgF 2, CaF 2, La F 3 iridium alucones &...

© Fraunhofer IOF

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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

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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

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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

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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

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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

http://www.marquardt-kempen.de/s/cc_images/cache_2435481376.jpg?t=1362993658

© Fraunhofer IOF

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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

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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle

ALD atomic layer-by-layer coat ing technology

© Fraunhofer IOF

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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle


© Fraunhofer IOF

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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle


© Fraunhofer IOF

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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle

Ar purge


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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle

Ar purge


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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle

Ar purge

Ar purge


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HSi(N(CH3)2)3

O2 Plasma

SiO2 ALD cycle

Ar purge

Ar purge


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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

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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

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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

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Out l ine

In t roduct ion

Coat ing equipm ent

Resul t s

Materia ls



Out look

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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

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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

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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

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TiO2 Film Grow th

Linear ALD growth with number of cycles Influence of Deposit ion Tempera ture and O2-Plasma

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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

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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

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TiO2 Tensile Mechanical St ress

σ decreases in nanolamina tes

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HfO2

Tet rakis(d imethylamino)hafn ium(IV)[(CH3)2N]4Hf

hea ted and bubbled a t 50°C

+ O2 Plasma

© Fraunhofer IOF

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Opt ical Propert ies – Inf luence of Temperature

high sca t te ring losses above 200°C deposit ion tempera ture

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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

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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

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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

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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)

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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

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Al2O3

Trimethyla luminum(CH3)3Al

own vapour pressure

+ H2OO2 Plasma

Aluminum chlorideAlCl3

+ H2O

© Fraunhofer IOF

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100 nm Al2O3 on 200 mm Si w afer

© Fraunhofer IOF

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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

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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

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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

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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

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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

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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

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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

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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

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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



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

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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


Ref

lect

ance

(%)

Wavelength (nm)

AOI=45°

500 550 1000 1050 11000

1

2

3

4


Ref

lect

ance

(%)

Wavelength (nm)

AOI=45°

© Fraunhofer IOF

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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



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]

mailto:[email protected]

© Fraunhofer IOF

Page 59

Acknow ledgement

Andreas TünnermannErnst Bernhard KleyUwe ZeitnerPe te r MunzertUlrike SchulzNorbert Kaiser

IAP and IOF co l leagues

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Overview of ALD -Activities for Optical Applications: …MgF 2, CaF 2, La F 3 iridium alucones &...

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