Thin films seen in the light of high energy synchrotron radiation: stress and microstructure...
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Transcript of Thin films seen in the light of high energy synchrotron radiation: stress and microstructure...
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Thin films seen in the light of high energy synchro-tron radiation: Stress and microstructure analysis using energy-dispersive diffraction Dept. of Microstructure and
Residual Stress Analysis
Ch. Genzel
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Outline
BESSY II Introduction Angle- vs. energy-dispersive
diffraction Basic principles of X-ray stress
analysis (XSA)
Examples XSA on coated cutting tools Stress and composition gradients In-situ study of thin film processing What about the microstructure?
Summary
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 20143
The Mission of the Helmholtz-Zentrum Berlin
WannseeBER II Reactor
AdlershofBESSY II
Two large scale facilities for investigating the structure and function of matterEnergy research
SynchrotronNeutrons
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 20144
Department of microstructure and residual stress analysis
Synchrotron
ASAXS
Diffraction:Stress, texture, microstructure
Scattering:Nanostructure
Imaging:
E3
Neutrons
Synchrotron
EDDI
Time resolution
Depth resolution
Spatial resolution
X-ray
ETA
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Thin films and coatings in every day use
CISCIS
Thin films and coatings fulfill various important functions in our daily life …
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Designing of property-enhanced coating systems
Composition &Microstructure Texture
Residual stress
Al2O3
TiCN
Coating properties can be tailored in the manufacturing process.
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
The role of diffraction methods ...
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Information provided by X-ray diffraction
Energy [keV]
Inte
nsity
[a. u
.]
afterbefore sulphurization
X-Ray Diffraction: Crystal structureNondestructivePhase-selectiveInformation depth nm ... cm
Line width and shape: Domain/particle size Microstrain, lattice defects
Line intensity: crystallographic texture Reaction kinetics
Fluorescence lines: Element distribution
Line position and shift: Crystal structure Residual stresses
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 20149
Challenges in structural research with diffraction methods
9
Investigations should be done ...
... in situ (time resolution)
0 5 mint ... with high spatial resolution
zxy
... under service conditions
sload
RT
1000 ºC
T
Thin films: Superposition of gradients of residual stress, texture and composition on very limited space!
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Well-known and mainly used: Angle-dispersive X-ray diffraction
0D: Scintillation counter 1D: Position sensitive det. 2D: Channel plate
2q
Photon source
monochromatic X-ray beam
2q [deg]
30 40 50 60 70 80 90
0
5
10
15
I [cp
s]
CoKa surface sensitive (low energies) high angular resolution long counting times (scintillation
counter) complex experimental setup
variable!substrate
coating
10
E1 = E2 = E3 …
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Features of energy-dispersive X-ray diffraction
fixed!
white beam
substrate
Fixed experimental setup Complete diffraction patterns
in fixed directions (unique!) Different diffraction lines Ehkl
originate from different depths
coating
E1 < E2 < E3 …
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 201412
Strategy for coating stress analysis
Materials Science Beamline EDDI
ETA diffractometer
Angle-dispersive diffraction (lab) Low energies (5 … 17 keV) Surface sensitive
coating
substrate
Energy-dispersive diffraction (synchrotron) Energies up to 120 keV Sensitive in deeper zones
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
The EDDI beamline for Energy Dispersive DIffraction
EDDI@BESSY II: E (8 … 120) keV 2.4·1011 ph·s-1/0.1% bw
Experimental hutch
PVD chamber Two detector setup
DHS 1100 heating station Mechanical load device
High resolution setup
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Basic principles of X-ray stress analysis
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Principle of residual stress analysis by diffraction methods
angle-/energy-dispersive
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1. Measurement of the diffraction line shift for various orientations ( ,j y)
2. Evaluation of the lattice strain
3. Evaluation of the residual stress tensor via Hooke‘s law.
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
The sin2 -y method
0 1
In-plane homogeneous film with biaxial residual stress state:
Fundamental equation of X-ray stress analysis takes the form:
Residual stress (s z) require a more sophisticated treatment ...
m > 0: tensile stress
m < 0: compressive stress
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
XSA on coated cutting tools
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 201418
XSA on multilayer systems: Influence of the coating design
5µmWC
TiCNAl2O3
WCTiCN
Al2O3
10µm
„Thin“system (D = 5 µm) „Thick“system (D = 18 µm)
TiCN
0.2 0.4 0.6 0.8 1 0.0873
0.0875
0.0877
0
d42
2[n
m]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1 0.0873
0.0875
0.0877
0
d42
2[n
m]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1
0.08750
0.08755
0.08760
0
d422
[nm
]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1
0.08750
0.08755
0.08760
0
d422
[nm
]
sin²
blasted
as-grown
CuKa
Al2O
3
0.2 0.4 0.6 0.8 1
0.172
0.174
0.176
0
d024
[nm
]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1
0.172
0.174
0.176
0
d024
[nm
]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1
0.1715
0.1725
0.1735
0.1745
0
d024
[nm
]
sin²
blasted
as-grown
0.2 0.4 0.6 0.8 1
0.1715
0.1725
0.1735
0.1745
0
d024
[nm
]
sin²
blasted
as-grown
CuKasteep stress gradient!
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
ED-XSA in the interfacial substrate zone
30 40 50 60
200
400
600
800
1000
E [keV]
I [ct
s]
001-
WC
101-
WC
110-
WC
002-
WC
111-
WC
100-
WC
coating reflections
30 40 50 60
200
400
600
800
1000
E [keV]
I [ct
s]
001-
WC
101-
WC
110-
WC
002-
WC
111-
WC
100-
WC
coating reflections
2q = 9°2q = 9°
5µmWC
TiCN
Al2O3
E1 < E2 < E3
M. Klaus et al., Thin solid films 517 (2008), 1172.
1 2 3 4 5 6 7
-1.5
-1.0
- 0.5
0
001
111
002
110
101
001
0
||[G
Pa]
[µm]
blasted
as-grown
1 2 3 4 5 6 7
-1.5
-1.0
- 0.5
0
001
111
002
110
101
001
0
||[G
Pa]
[µm]
blasted
as-grown
coating
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Application of the sin2y-method to each line Ehkl
Assignment of the obtained stress values <shkl> to average information depth <thkl>
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
5µmWC
TiCNAl2O3
z [µm]
4 8 12 16 20
- 6
- 4
- 2
0
2
0
- 8
||
[GP
a] TiCN
TiN
Al O 3
BL
as-grown
blasted
2
WCTiCN
Al2O3
10µm
z [µm]
1 2 3 4 5
- 6
- 4
- 2
0
2
0
- 8
||
[GP
a]
TiCN
TiN
Al O B
L
as-grown
blasted
2 3
1 2 3 4 5 6 7
-1.5
-1.0
- 0.5
0
001
111
002
110
101
001
0
||[G
Pa]
[µm]
blasted
as-grown
1 2 3 4 5 6 7
-1.5
-1.0
- 0.5
0
001
111
002
110
101
001
0
||[G
Pa]
[µm]
blasted
as-grown
1 2 3 5 6 7
-1.5
-1.0
-0.5
0
111
002
110
101
001
0 4
||[M
Pa]
[µm]
blasted
unblasted
1 2 3 5 6 7
-1.5
-1.0
-0.5
0
111
002
110
101
001
0 4
||[M
Pa]
[µm]
blasted
unblasted
Interlayer gradient: Balance between coating and substrate
Intralayer gradient: Balance within the Al2O3 top layer
Residual stress balance in multilayer systems
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014 21
Separation of residual stress and composition gradients
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 201422
Residual stress analysis in expanded austenite layers
2q = 8°
111-N
111
200-N 200
Substrate
Exp. austenite
S. Jegou et al. Thin solid films 530 (2013), 71.
Residual stress (-N) Composition (-N) Strain depth profiling
in the scattering vec-tor mode.
Application of the sin² method for predefined depths .
t = 5 µmm
sin2y*
d0
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Energy-dispersive diffraction:In-situ study of thin film processing
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 201424
Rapid thermal processing (RTP) of CuInS2 thin films
Sulphurization of Cu/In precursor on Mo/glass substrate
Sulphurization chamber mounted on the diffractometer.
Fast recording of ED spectra
Indium
CopperMolybdenium
Glass
metallic precursor
CuInS2
Sulfur
DE
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
The two-detector setup @ EDDI
Simultaneous acquisition of diffraction patterns in fixed but arbitrary measuring directions!
High resolution In-situ
sin²y
dy
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
In-situ analysis of thermal stresses in thin Mo films on glass
Ch. Genzel et al., J. Strain Analysis 46 (2011), 615
Mo = 510-6 K-1 / Glass = 9.510-6 K-1
sin2y-based stress analysis
Ds
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
What can we learn about the microstructure?
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014 28
In-situ microstructure analysis: recrystallization of CuInS2
10 50 100 150 Process time [min]
Ene
rgy
[keV
]
30
Substrate temperature [ºC]50 150 250 350 450
Recrystal-lization
H. Rodriguez-Alvarez, PhD thesis, TU Berlin, 2010.
112- CuInS2
Small-grained, defective CuInS2
Recrystallized CuInS2
Driving Forces?Enhancement?
112- CuInS2
29 30 31 32 33Energy [keV]
Lorentzian, broad
Nor
mal
ized
Int
ensi
ty [
a. u
.]
Gaussian, small
Energy-dispersive diffraction line profile analysis?
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Instrumental resolution in ED diffraction (EDDI beamline)
Instrumental resolution:
( G – Full width at half maximum)
LaB6 SRM660b Energy-dispersive RIETVELD refinement:
D. Apel et al., Z. Kristallogr. 226 (2011), 943.
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Multiple vs. single line analysis
2 = 10°CeO2 ED Rietveld study of size-related
broadening in ceria powder: EDDI: DV = 226(31) Å+)
Size-Strain RR: DV = 221…236 Å++)
+) D. Apel et al., Z. Kristallogr. 226 (2011), 943.++) D. Balzar et al., JAC 37 (2004), 911.
112- CuInS2
29 30 31 32 33Energy [keV]
Nor
mal
ized
Int
ensi
ty [
a. u
.]
Energy [keV]
Inte
nsity
[co
unts
x 1
03 ] Needs single line analysis!
30
XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Single line analysis of domain size and microstrain
D. Thomas, PhD thesis, TU Berlin, 2012.
Broadening angle dispersive energy dispersive
Size
Strain
Size and strain broa-dening depend on q!
Only strain broade-ning depends on E!
Line profiles described by pseudo-Voigt (pV) functions:
pV(E) = x·Cauchy(E) + (1-x)·Gaussian(E) (0 x 1) Domain size Cauchy width bC
Micro strain Gaussian width bG
dom
ain
size
[nm
]
interrupt temperature [°C]
mic
ro s
trai
n [%
]
initial state
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Summary
Energy-dispersive synchrotron X-ray diffraction: Versatile tool for many fields of materials sciences.
Under fixed diffraction conditions complete diffrac-tion patterns are recorded.
Thin film analysis and (high energy) ED diffraction fit together! The methods allows for:o (Residual) stress analysis, even in complex cases (multi-
layers, separation of stress and composition gradients ...)o Fast in-situ study of thin film growth processeso Microstructural characterization (ED line profile analysis)o ...
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
My special thanks go to:Manuela KlausIngwer A. DenksRodrigo CoelhoDaniel ApelDiana ThomasMatthias MeixnerTillman FussGuido Wagener
Roland MainzHumberto Rodriguez-Alvarez
Davor Balzar
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XIII Brazilian MRS meeting, João Pessoa, Brazil, September 28 – October 02, 2014
Thank you very much for your attention!
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