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Short Course onX-ray diffraction analysis of thin films and surfaces: i. Glancing/grazing incident XRD (GIXRD)ii. Residual stress analysis (RSA)
Pio John Buenconsejo (Dr)FACTS Scientisthttp://research.ntu.edu.sg/facts
5/March/2019 FACTS short course, Buenconsejo 1
Content
Background: X-ray analysis of thin film materials Glancing/grazing incident X-ray
diffraction Residual stress analysis by XRD Summary
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What is a thin film sample?
Prepared by: Coating or deposition Chemical or Physical reaction
Characteristics: Thickness, roughness, density,
porosity, residual stress, topology, structures
Crystallinity, orientation, ordering, composition, defects, epitaxial strain
Applications: Electronic devices Sensors & MEMS devices Surface science & engineering
Film 1 mm to 10 mm Thin film 10 nm to 1 mmUltra thin film 10 nmSurface or monolayer < 1 nm
Thin film
Substrate
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X-ray interaction with thin films
Incident X-rays are reflected/scattered/diffracted:• X-ray reflectivity (XRR) • X-ray scattering (SAXS, GISAXS)• X-ray Diffraction (PXRD, GIXRD
GIWAXS, HRXRD)
Incident X-rays excites the sample to produce signals:• X-ray Fluorescence (XRF)• X-ray Photon Emission (XPS)
Thin film
Substrate
Incident X-rays• Laboratory source• Synchrotron source
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X-ray analysis of thin film materials
Amorphous Non-crystalline Thickness Roughness Density Nano-structure
Thin film
Substrate
Polycrystalline Crystalline, Phase ID Randomly oriented Thickness Roughness Density Nano-structure Residual stress
Textured Crystalline, Phase ID Preferred
orientation Thickness Roughness Density Nano-structure Residual stress
Epitaxial Single crystal Orientation Thickness Roughness Density Nanostructure Epitaxy, strain,
defects, composition
PXRD or TFXRDPFHRXRD XRRGISAXS/WAXS
RSA
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X-ray analysis of thin films and surfaces in FACTS
Instrument PXRDTFXRD PF XRR GISAXS
GIWAXS RSA HRXRD
XRD Cluster 1Shimadzu XRD
XRD Cluster 2Bruker D8 AdvancePanalytical X’pert Pro
Bruker D8 Discover* Xenocs Nanoinxider**
*In-situ heating RT to 1100C **In-situ cooling-heating, -150C to 350C Limited capability
PXRD Powder XRD (Bragg-Brentanno, 2q-q scan)TFXRD Thin film XRD (Glancing/grazing angle, 2q scan)PF Pole figure (phi-,chi-scan)XRR X-ray reflectometry (specular and off-specular)GISAXS Grazing Incidence Small Angle X-ray Scattering (in/out-of-plane)GIWAXS Grazing Incidence Wide Angle X-ray Scattering (in/out-of-plane)RSA Residual stress analysis (sin2y, multiple-hkl, whole pattern decomposition)HRXRD High resolution XRD (2q-w, w-2q, rocking curve, phi-, chi-scan)
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PXRD and TFXRDWhat’s the difference?
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PXRD (q/2q) versus TFXRD (GIXRD)
T. Ryan, Journal of Chemical Education 79(5) 2001, 613-616
1. Why is there a difference in diffraction geometry?2. How much absorption and penetration depth?
Bragg-Brentanno: q/2q scanGIXRD: 2q scan at fixed q or a
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q/2q diffraction geometry
Scattering plane
QDiffraction/scattering vector
XD
q 2q
Scattering plane
(hkl)1 (hkl)2 (hkl)3
nl =2dsinq Bragg condition Scattering/Diffraction vector is
always normal to the surface q/2q is a symmetric scan hkl parallel to the surface Penetration depth is not controlled Coplanar configuration
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q/2q : Bragg-Brentanno geometry
Powder XRD: Bragg-Brentanno (parafocusing) geometry Divergent beam optics:
- Including crystals with tilted hkl normal Angular resolution can be improved with narrow
slits
hkl
Diffraction vectorX D
2qq Div. slit
Bragg-Brentanno geometry with optics
Focus length
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q/2q: Bragg-Brentanno geometry
X D
Goniometer circle
Focusing circle
q 2q
in-focusout-of-focus out-of-focus
R= 320 mm (dashed curves)= 240 mm (solid curves)
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q/2q GIXRD diffraction geometry
X D
Goniometer circle
Focusing circle
q 2q X
D
Focusing circle
Goniometer circle
a
2q-a
Only one point is in focus Requires narrow/parallel incident beam 5/March/2019 FACTS short course, Buenconsejo 12
GIXRD diffraction geometry
Thin film XRD: Glancing or Grazing incident angle Asymmetric scan, non-parafocusing Incident/diffracted parallel beam Controlled penetration depth Sample surface flat alignment is important
(surface & height) Diffraction vector is not parallel to the sample
surface normal
hkl
Diffraction vector
X
D
2q
a
a
Scattering plane
(hkl)1 (hkl)2 (hkl)3
Beam footprint with parallel beam on the sample
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Beam footprint in GIXRD (parallel beam)
Beam footprint (B):
a
BW = beam width
0 1 2 3 41
10
100
1000
B (
mm
)
a (o)
Beam width 0.1 mm 0.2 mm 0.6 mm 1 mm
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Goebel mirror
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Examples: GIXRD versus BBG scan
40 60 80 1001000
10000
100000
1000000
1E7
1E8
1E9
1E10
1E11
1E12
1E13
0
20000
40000
60000
80000
100000
Log
Inte
nsi
ty
2q (o)
q-2q scan substrate
(222)fcc
(311)fcc(220)
fcc
(200)fcc
Inte
nsity
GIXRD a =1o
63Au-35Cu-2Al thin film fcc-phase
t = 681 nm
Substrate: SiO2/Si-001
(111)fcc GIXRD:
Probes the thin film region only Relative Intensity is lower
Bragg-Brentanno (q/2q scan): Additional contribution from the
substrate Very high intensity
How much difference in the absorption and penetration depth?
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X-ray absorption and penetration depth
Lambert-Beer law (X-ray absorption):
µ = linear absorption coefficient = µmrµm = mass absorption coefficient r = mass densityl = X-ray path length
Penetration depth⁄ (normal incidence)⁄ (non-normal incidence)
X-ray absorption effects on materials: X-ray absorption follows Lambert-Beer law which relates the attenuation of light
(electromagnetic radiation) travelling through a material to the material’s properties. Penetration depth is the depth at which the intensity of radiation incident on a
material is attenuated to 1/e (37%).
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q/2q scan: Absorption factor
Ref: Thin Film analysis by X-ray Scattering, Birkholtz
Io Io exp(-2ml)
zl l
q q
t𝑤ℎ𝑒𝑟𝑒: 𝑙 =
𝑧
𝑠𝑖𝑛𝜃
/ Absorption factor:
A = ∫ ( )
∫ ( )
Intensity is attenuated by:
Solution of the integral:
Infinitely thick sample:
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q/2q: Absorption factor
Absorption factor:
/
Ref: Thin Film analysis by X-ray Scattering, Birkholtz
Diffraction intensity from a polycrystalline sample:
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q/2q: Penetration depth
Ref: Thin Film analysis by X-ray Scattering, Birkholtz
𝟏𝒆⁄
𝟏𝝁 normal incidence
Penetration depth
5/March/2019 FACTS short course, Buenconsejo 20
GIXRD: Absorption factor
Thin Film analysis by X-ray Scattering, Birkholtz
Io
Io exp(-ml)
zl1
l2
a2q - a
t
X-ray path length:
𝑘 =1
𝑠𝑖𝑛𝛼+
1
sin (2𝜃 − 𝛼)
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GIXRD: X-ray penetration depth
Thin Film analysis by X-ray Scattering, Birkholtz
/
1. Attenuation of X-rays to 1/e of its initial value
2. t63 for AGIXRD = 1-1/e (mt63ka = 1, 63%) May exceed the thickness of a thin layer
3. Information depth, based on weighted average over the sampling depthfor infinitely thick-layer it approaches t63
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GIXRD: X-ray penetration depth
40 60 80 1001000
10000
100000
1000000
1E7
1E8
1E9
1E10
1E11
1E12
1E13
0
20000
40000
60000
80000
100000
Log
Inte
nsi
ty
2q (o)
q-2q scan substrate
(222)fcc
(311)fcc(220)
fcc
(200)fcc
Inte
nsity
GIXRD a =1o
63Au-35Cu-2Al thin film fcc-phase
t = 681 nm
Substrate: SiO2/Si-001
(111)fcc
a=1o
depth =55 nm
q > 15o
depth > 900 nm
---Note-----i) Porosity, columnar grains, voids, defects in the material could reduce the effective density of the film and therefore the penetration depth could be deeper. ii) Thin film density could be measured using XRR.
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Useful links for X-ray penetration depth
Online penetration depth calculator:http://gixa.ati.tuwien.ac.at/tools/penetrationdepth.jsf
Absorption coefficient reference:https://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.htmlhttps://physics.nist.gov/PhysRefData/FFast/html/form.html
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GIXRD at a ~ ac
Near ac: Very surface sensitive GIXRD (in-plane
scattering/diffraction)
/
/
4. Penetration depth:
Absorption limited
Total reflection
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GIXRD: Out-of-plane scattering/diffraction
Scattering plane
QDiffraction/scattering vector
X
D
a2q-a
a
Scattering plane
(hkl)1 (hkl)2 (hkl)3
a is constant a ≈ arcsin(mt) Thickness/depth information
profile (microstructure, strain, phase)
Coplanar configuration GISAXS, GIWAXS out plane
scattering
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GIXRD: In-plane scattering/diffraction
QX
ai
afScattering plane D
ai
(hkl)1
af
(hkl)2
Scattering plane
Scattering plane is almost parallel to the surface
ai, af are constant and very small almost near the surface plane
Evanescent wave (few nm of the surface) depth information: ai a~arcsin(mt) hkl-planes perpendicular to the surface GISAXS, GIWAXS, -inplane scattering
5/March/2019 FACTS short course, Buenconsejo 28
GIXRD: 2D diffraction
QDiffraction/scattering vector
Xa
qz
(+)qx
qz
(+)qx
(-)qx
2D detector: Captures the out-of-plane
and in-plane diffraction Good for GISAXS/GIWAXS
experiments Anisotropy or preferred
orientation
x
y
zD
D
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GIXRD: 2D diffraction
QDiffraction/scattering vector
Xa
qz
(+)qx
qz
(+)qx
(-)qx
2D diffraction: Makes sense with
point X-ray source
x
y
z
This will not work for a Line beam X-ray source5/March/2019 FACTS short course, Buenconsejo 30
2D diffraction: GIWAXS in-plane and out-of-plane example
More of this technique in GISAXS/GIWAXS short course
5/March/2019 FACTS short course, Buenconsejo 31
Residual stress analysis by X-ray Diffraction
5/March/2019 FACTS short course, Buenconsejo 32
Residual stress in materialsOrigin: Thin-film/substrate
difference in mechanical properties multi-layer stack
Surface deformation nanocrystallization or amorphization by mechanical deformation
Micro(nano)-structures porosity, defects 2D or 3D structures Composite structures
Extrinsic or Intrinsic
Why do we need to quantify it? Reliability & performance Processing & product development Functional properties Failure analysis
5/March/2019 FACTS short course, Buenconsejo 33
Residual stress
Macrostress: Average over many grains sI Diffraction peak shifts sin2y method and its
variants
Microstress: Grain-specific, internal sII & sIII Diffraction peak shift and
broadening Diffraction peak shape
analysis: • Williamson-Hall (Acta
Metall. 1 (1953) 22).• Warren-Averbach• Whole pattern fitting
5/March/2019 FACTS short course, Buenconsejo 34
X-ray residual stress analysis
Specimen
homogeneousInhomogeneous
polycrystallineSingle-crystalline
Isotropic material
Quasi-isotropic
Anisotropic
Simple Mechanical constants (E, v)
Relatively simple hkl dependent elastic constants X-ray elastic constants (XEC) Complicated Texture, grain-interaction models X-ray stress factors (XSF)
Data collection?Data analysis?
5/March/2019 FACTS short course, Buenconsejo 35
Basic elasticity equations
: strain: stress
: compliance tensor: elastic stiffness
s11
s12
s13
s31
s32
s33
s21
s22
s23
Stress tensors in the sample reference frame
Hooke’s law
Isotropic materials:
E (Young’ modulus) and n (Poisson’s ratio) are materials dependent mechanical constants
5/March/2019 FACTS short course, Buenconsejo 36
Elastic constants__________________________________________Triclinic None (or center of symmetry)Monoclinic 1 twofold rotationOrthorhombic 2 perpendicular twofold rotationTetragonal 1 fourfold rotation around [001]Rhombohedral 1 threefold rotation around [111]Hexagonal 1sixfold rotation around [0001]Cubic 4 threefold rotations around <111>
Anisotropy factor
Cubic
5/March/2019 FACTS short course, Buenconsejo 37
X-ray residual stress analysis
SS3
SS1
SS2
L2
L1
L3y
f
Sample reference frame: SS1 SS2 SS3 SS3 = Surface normal SS1 & SS2 are in-plane (surface)
directions
Laboratory reference frame: L1 L2 L3 𝐿 = 𝐿 = Diffraction vector
𝜀 = 𝜀
f in-plane rotation angle
y azimuth angle
Tensor transformation applied to express the strain (stress) in the sample coordinate system
Fundamental equation for x-ray residual stress analysis:
𝜀 =1
2𝑆 𝜎 𝑐𝑜𝑠 𝜙 + 𝜎 𝑠𝑖𝑛 𝜙 + 𝜎 𝑠𝑖𝑛2𝜙 𝑠𝑖𝑛 𝜓 + 𝜎 𝑐𝑜𝑠𝜙 + 𝜎 𝑠𝑖𝑛𝜙 𝑠𝑖𝑛2𝜓 + 𝜎 𝑐𝑜𝑠 𝜓
+𝑆 (𝜎 + 𝜎 + 𝜎 )
5/March/2019 FACTS short course, Buenconsejo 38
X-ray residual stress analysis
SS1
SS2
SS3𝝓𝝍y
f
Fundamental equation for x-ray residual stress analysis:
𝜀 = 𝜀 =1
2𝑆 𝜎 𝑐𝑜𝑠 𝜙 + 𝜎 𝑠𝑖𝑛 𝜙 + 𝜎 𝑠𝑖𝑛2𝜙 𝑠𝑖𝑛 𝜓 + 𝜎 𝑐𝑜𝑠𝜙 + 𝜎 𝑠𝑖𝑛𝜙 𝑠𝑖𝑛2𝜓 + 𝜎 𝑐𝑜𝑠 𝜓
+𝑆 (𝜎 + 𝜎 + 𝜎 )
𝐵𝑟𝑎𝑔𝑔 𝑠 𝑙𝑎𝑤: 𝜆 = 2𝑑 𝑠𝑖𝑛𝜃
= Diffraction vector
𝒅𝒉𝒌𝒍
s11
s12
s13
s31
s32
s33
s21
s22
s23
X-ray elastic constants:
5/March/2019 FACTS short course, Buenconsejo 39
How do we collect RSA data?
Conventional diffraction geometry: y: angle between sample (S3) and
diffractometer (L3) Can be done as c or w tilt or both Single hkl (set at the Bragg angle 2qhkl)2q
L3//SS3
x d
y = 0
q
w/q
L3SS3 y
2q
x d
q
w/q
c tilt
c=y
2q
x d
q
w/q
L3 SS3
yw tilt
y
w
5/March/2019 FACTS short course, Buenconsejo 40
How do we collect RSA data?
Conventional diffraction geometry: y: angle between sample (S3) and
diffractometer (L3) Can be done as c or w tilt or both Single hkl (set at the Bragg angle 2qhkl)2q
L3//SS3
x d
y = 0
q
w/q
2q
x d
q
w/q
L3 SS3
yw tilt
y
ww
Scattering plane
(-) y
SS3y
L3
w w
SS3 y
L3
SS3 L3
(0) y (+) y Maximum y tilt is limited by q Penetration depth is not controlled 2q-w scan mode5/March/2019 FACTS short course, Buenconsejo 41
How do we collect RSA data?
Conventional diffraction geometry: y: angle between sample (S3) and
diffractometer (L3) Can be done as c or w tilt or both Single hkl (set at the Bragg angle 2qhkl)2q
L3//SS3
x d
y = 0
q
w/q
y-tilt is not limited by q Chi (c) scan in a Eulerian cradle y-tilt in GIXRD is possible (fixed a),
penetration depth is controlled
L3SS3 y
2q
x d
q
w/q
c tilt
c=y
L3
SS3
L3
SS3
L3
SS3
(+)y (0)y (-)y
5/March/2019 FACTS short course, Buenconsejo 42
(+)qx
(-)qx
qz
How do we collect RSA data?
Conventional diffraction geometry: y: angle between sample (S3) and
diffractometer (L3) Can be done as c or w tilt or both Single hkl (set at the Bragg angle 2qhkl)2q
L3//SS3
x d
y = 0
q
w/q
2D-diffraction simultaneously captures various y-tilt (c azimuth)
GIXRD, penetration depth controlled
L3SS3 y
2q
x d
q
w/q
c tilt
c=y
SS3
(+)y (-)y
L3
(+)y
5/March/2019 FACTS short course, Buenconsejo 43
How do we collect RSA data?
Grazing incident geometry: y: angle between sample (S3) and
diffractometer (L3) y tilt by 2q scan multiple hkl (as set by the Bragg angle
2qhkl) 2D diffraction will require no tilting Penetration depth is controlled
2q
SS3
x
d
a
w/q
yL3
Grazing incident @ fixed a
2q
SS3
x
d
a
w/q
yL3
2q scan
a
Scattering plane
(hkl)1 (hkl)2 (hkl)3
SS3y
L3
SS3yL3
SS3y
L3
a a
y-tilt by 2q scan will require multiple hkl5/March/2019 FACTS short course, Buenconsejo 44
FACTS XRD
2qq/w
SS3
𝝓𝝍y = 0
w
Scattering plane
(-) y
SS3y
L3
w w
SS3 y
L3
SS3 L3
(0) y (+) y
q/w2q
SS3𝝓𝝍
D8 Discover: Horizontal goniometerD8 Advance: vertical goniometer
Eulerian cradle
w-tilt c-tilt GIXRD f-rotation
w-tilt
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Residual stress data analysis
I. Single hkl• Triaxial, biaxial, uniaxial
II. Multiple hkl• g(y, hkl), f(y, hkl)
III. General least-squares analysis of any stress state• Non-linear least square fitting algorithms
e
sin2y
e
sin2y
y>0
y<0 e
sin2y
X-ray Elastic Constant:
sin2y 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
y 18.43 26.57 33.21 39.23 45 50.77 56.79 63.43 71.57
X-ray Stress Factor:
Fundamental equation for x-ray residual stress analysis:
𝜀 = 𝜀 =1
2𝑆 𝜎 𝑐𝑜𝑠 𝜙 + 𝜎 𝑠𝑖𝑛 𝜙 + 𝜎 𝑠𝑖𝑛2𝜙 𝑠𝑖𝑛 𝜓 + 𝜎 𝑐𝑜𝑠𝜙 + 𝜎 𝑠𝑖𝑛𝜙 𝑠𝑖𝑛2𝜓 + 𝜎 𝑐𝑜𝑠 𝜓
+𝑆 (𝜎 + 𝜎 + 𝜎 )
variation of y at constant f
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Non-linear: Textured materials Gradient stress Shear stress
SS1
SS2
efyy
f
SS3
Single hkl analysis
112 114 116 118 1200
200
400
600
800
1000
1200
1400
1600
1800
2000
+y
2q
-y
f = 0
112 114 116 118 120
2q
f = 45
112 114 116 118 120
2q
f = 90
Material: Au71Cu25Al4 thin filmfcc-AuCu(Al) phasethickness = 725 nm
hkl (331) at 2q = 116.23
Young’s modulus = 79 GPaPoisson’s ratio = 0.44Arx = 2.8
S1 = -4.153E-6; 1/2S2 = 1.398E-5
Fundamental equation for x-ray residual stress analysis:
𝜀 = 𝜎 𝑐𝑜𝑠 𝜙 + 𝜎 𝑠𝑖𝑛 𝜙 + 𝜎 𝑠𝑖𝑛2𝜙 𝑠𝑖𝑛 𝜓 + 𝜎 𝑐𝑜𝑠𝜙 + 𝜎 𝑠𝑖𝑛𝜙 𝑠𝑖𝑛2𝜓 + 𝜎 𝑐𝑜𝑠 𝜓
+𝑆 (𝜎 + 𝜎 + 𝜎 )
5/March/2019 FACTS short course, Buenconsejo 47
Single hkl analysis
0.0 0.2 0.4 0.6 0.8 1.0-0.004
-0.002
0.000
0.002
0.004-0.004
-0.002
0.000
0.002
0.004
0.0 0.2 0.4 0.6 0.8 1.0
-0.004
-0.002
0.000
0.002
0.004
stra
in
sin2y
f = -90
f = -45
stra
in
f = 0 -y +y
stra
in
Stress tensor (MPa) =
Triaxial stress analysis:
s11
s12
s13
s31
s32
s33
s21
s22
s23
Principal stress tensor (MPa) =
Biaxial stress!5/March/2019 FACTS short course, Buenconsejo 48
Single hkl analysis: sin2y variants
𝜎 =𝜎 0 00 𝜎 00 0 0
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 2𝑆 𝜎
𝜎 =𝜎 𝜎 0𝜎 𝜎 00 0 0
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 )
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 )
𝜀 = 𝑆 + 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 )
𝜎 =𝜎 0 00 0 00 0 0
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 𝜎Uniaxial
𝜎 =𝜎 0 00 𝜎 00 0 0
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 )
𝜀 = 𝑆 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 )
Biaxial
Biaxial Rotationally symmetric
Biaxial principal stress
Triaxialprincipal stress 𝜎 =
𝜎 0 00 𝜎 00 0 𝜎
𝜀 = 𝑆 𝜎 − 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 + 𝜎 )+ 𝑆 𝜎
𝜀 = 𝑆 (𝜎 +𝜎 + 𝜎 )+ 𝑆 𝜎
𝜀 = 𝑆 𝜎 − 𝜎 𝑠𝑖𝑛 𝜓 + 𝑆 (𝜎 +𝜎 + 𝜎 )+ 𝑆 𝜎
5/March/2019 FACTS short course, Buenconsejo 49
Multiple hkl analysis
Material: Au71Cu25Al4 thin filmfcc-AuCu(Al) phasethickness = 725 nm
Young’s modulus = 79 GPaPoisson’s ratio = 0.44Arx = 2.8
40 60 80 100 12010
100
1000
10000
100000
a = 20
420
331
400
22231
1220
111
Inte
nsity
2q
200
a = 0.5
-0.000006 -0.000004 -0.000002 0.000000 0.000002
-0.0008
-0.0006
-0.0004
-0.0002
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
stra
in
f (y, hkl)
a =0.5
0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40400
500
600
700
800
900
1000
1100
Axial stress
Axi
al s
tres
s
thickness, mm
GIXRD
5/March/2019 FACTS short course, Buenconsejo 50
Multiple hkl analysis
g(y, hkl) method:Biaxial stress state 𝑔 𝜓, ℎ𝑘𝑙 =
𝑆𝑠𝑖𝑛 𝜓
= 𝑔 𝜓, ℎ𝑘𝑙 𝜎 + (𝜎 +𝜎 )
= 𝑔 𝜓, ℎ𝑘𝑙 𝜎 + (𝜎 +𝜎 )
= 𝑔 𝜓, ℎ𝑘𝑙 + 𝜎 + 𝜎 +𝜎
f(y, hkl) method:Rotationally symmetric Biaxial stress state
𝑓 𝜓, ℎ𝑘𝑙 = 2𝑆 + 𝑠𝑖𝑛 𝜓 𝜀 = 𝑓 𝜓, ℎ𝑘𝑙 𝜎
5/March/2019 FACTS short course, Buenconsejo 51
General least-square analysis of any stress state
wi is weighting factor ss is a fitting parameter
Most general solution Requires more computing power Non-linear least squares fitting Can combine single hkl and multiple hkl
data Works well with textured (highly
anisotropic) samples For highly anisotropic samples it requires
use of grain-interaction models (XSF)
5/March/2019 FACTS short course, Buenconsejo 52
Summary
q/2q scan vs GIXRD geometry X-ray absorption & penetration depth in-plane & out of plane diffraction
Residual stress analysis background on residual stress how to collect the data how to analyse the data
Suggested reading materials: “Residual Stress (Measurement by Diffraction and Interpretation)” Noyan, Cohen, 1987 Springer
“Thin film analysis by X-ray Scattering” Mark Birkholz
“Stress analysis of polycrystalline thin films and surface regions by XRD” Wezel, et. al. J. Appl. Crys. (2005) 38 1-29
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