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X-Ray Scattering Methods for Characterization of Advanced Materials Workshop<br />Characterization of layered structures b...
Outline<br />Thin films definition and XRD applications<br />Reciprocal Space definition<br />Characterization of Epitaxia...
Thin Film Definition<br />Nearly perfect epitaxy (thin film orientated to substrate parallel and perpendicular)<br />Imper...
Epitaxial Layers<br />Mismatch<br />Relaxation<br />Composition<br />In-Plane Epitaxy<br />Mosaic spread<br />Super-lattic...
Polycrystalline Layers<br />Phase ID<br />Quantification<br />Unit Cell refinement<br />Residual stress<br />Crystallite s...
Amorphous Layers<br />Thickness <br />Density <br />Roughness<br />}XRR<br />
Reciprocal Space<br />1/<br />S<br />1/<br />1/<br />2<br /><br /><br /><br />7<br />
The Reciprocal Lattice from Planes<br /><ul><li>Create reciprocal lattice (RL), where each point represents a set of plane...
Reciprocal Lattice and Scattering Vectors<br />Reciprocal lattice vector d*hkl<br />Length 1/d<br />Direction, normal to h...
Scattering Vectors Related to a Real Experiment<br />Psi<br />Phi<br />source<br />Detector<br />S<br /><br />2<br />sam...
Reciprocal Lattice of a Single Crystal in 3D<br />115<br />-2-24<br /><ul><li>There are families of planes
All planes in the same family have the same  length |d*|, but different directions
The family members have the same 3 indices (in different orders e.g. 400,040,004 etc)</li></ul>004<br />224<br />113<br />...
Characterization of epitaxial Layers<br />12<br />
Epitaxial Samples in RS<br /><ul><li>We investigate the fine structure of individual reciprocal lattice spots</li></ul>115...
Thin Layers and Multi-layers<br />115<br />224<br />004<br />113<br />-440<br /><ul><li>The reciprocal lattices of the cry...
RSM features bulk crystals<br />CTR = sample surface streak (and white radiation streak)<br />M = monochromator (or source...
surface normal<br />high quality substrate -sharp peak<br />broadening normal to sample surface<br />thin layers<br />d sp...
layer<br />substrate<br />thick layer with grading and overall curvature<br />thin<br />layer<br />mosaic<br />layer<br />...
4.8o<br />InGaAs tensile and compressive alternating multilayer on 001 InP substrate.<br />Bent multilayer sample<br />Sam...
19<br />Buffer Layer Structures<br />Relaxed Buffer layers as virtual substrates:e.g.	Si/Ge on Si	InGaAs on GaAs	GaN on Sa...
layer thickness<br />Tilt, thickness and lateral width<br />symmetric<br />asymmetric<br />Spread due to finite size effec...
Broadening effects on symmetric reflections<br />Omega broadening due to <br />Size effects<br />Omega broadening due to t...
Strained Layer<br />Q<br />at=aS<br />Layer<br />006<br />Substrate<br />L<br />004<br />224<br />-2-24<br />002<br />aS<...
Relaxed Layer<br />Q<br />Layer<br />Substrate<br />006<br />at= aL<br />L<br />aL<br />004<br />224<br />-2-24<br />002<...
Relaxed layers RSM<br />24<br />
Scans in reciprocal space (1)<br />/2 scan<br />2’<br />’<br />25<br />
Scans in reciprocal space (2)<br />2’’<br />’’<br />26<br />
Scans in reciprocal space (3)<br />q varied<br />2’’’<br />’’’<br />27<br />
Scans in  reciprocal space (1)<br />Rocking curve<br />2<br />’<br />28<br />
Scans in  reciprocal space (2)<br />Rocking curve<br />2<br />’<br />29<br />
Scans in  reciprocal space (3)<br />q constant<br />2<br />’’’<br />30<br />
Scans in  reciprocal space (4)<br />2<br />’’’<br />31<br />
In-plane definition<br />Symmetrical<br />Diffraction <br />Gonio Scan<br />Grazing Incidence<br />Diffraction <br />2 the...
In-Plane Diffraction<br />In-plane diffraction is a technique for measuring the crystal planes that are oriented perpendic...
In-Plane Diffraction<br />2Theta/Omega scan<br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br ...
In-Plane Diffraction<br />2Theta/Omega scan<br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br ...
In-Plane Diffraction – phi scan <br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br />220<br />...
RS Mapping<br />0<br />+<br />+<br /><br />-<br />+<br />2-<br />0<br />Omega offset<br />-<br />-<br />2Theta/omega<br...
Reciprocal Space Map<br />Qz<br />AlGaN/GaN MQW<br />GaN(0002)<br />Qx<br />38<br />
12/1/2009<br /> Si (224)  - 1D-mode with PIXcel<br /><ul><li>Reduced collecting time (1/10)
High dynamic range</li></ul>Si<br />SiGe<br />
X-ray diffraction - rocking curve<br />monochromator (collimator)<br />AlGaN layer<br />X-ray<br />source<br />Peak positi...
Characterization of Polycrystalline layersspace<br />41<br />
42<br />Definitions: Orientations of crystallites<br />Random orientation<br />Single crystal<br />Preferred orientation<b...
Polycrystalline random oriented<br />113<br />000<br />hkl <br />0 0 4<br />A sufficient number of randomly oriented cryst...
Textured samples <br /><ul><li>Non uniform reciprocal lattice
Different intensities at different directions</li></ul>Spherical shell radius 1/dhkl<br />S<br />2<br />2<br />1/dhkl<br...
Characterization of Polycrystalline thin films<br />Phase ID<br />Phase ID with depth profiling<br />Residual stress<br />...
Symmetric 2Theta/Omega “powder” scans<br />Phase ID in polycrystalline samples<br />2Theta/Omega scan<br />scattering vect...
Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />47<br />
Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />48<br />
Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />331<br />004<br />49<br />
Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />422<br />331<br />004<br />51...
Symmetric scan for thin films<br />In the case of very thin films the scattering volume will become smaller and smaller as...
Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />52<br />
Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />53<br />
Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />54<br />
Glancing Incidence - Diffraction 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />55<br />
56<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br /><br />ZnO<br />CIGS<br />0.45 deg<br...
57<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br /><br />ZnO<br />CIGS<br />0.45 deg<br...
58<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br />ZnO<br />=0.45<br />CIGS<br />0.45 d...
GIXRD in Reciprocal Space<br />powder<br />single crystal<br />Sampling only the random component of the studied sample.<b...
Residual Stress in Polycrystalline thin films<br />Non uniform reciprocal lattice<br />Different d-spacings at different d...
“Stress” Measurement<br />A stress measurement determines dhkl at a series of Psi positions<br />The sample is stepped to ...
Classical Residual Stress<br />Single hkl<br /><br /><br /><br /><br /><br /><br />62<br />
Calssical Residual stress<br />Measure (very small) peak shifts as a function of the sample tilt angle ‘psi’<br />Plot d-s...
Multiple hkl residual stress analysis<br />Analysis<br />Determine peak positions<br />Calculate offsets<br />(w-q)=wfixed...
Stress depth gradient <br />Very small angle of incidence <br /> analyzing stress near surface<br />Coating<br />Substrat...
Stress depth gradient <br />Larger angle of incidence <br /> analyzing stress near surface AND deeper<br />Coating<br />S...
Stress depth gradient <br />Largest angle of incidence <br /> analyzing average stress whole coating<br />Coating<br />Su...
Stress Gradient example - MgO on Glass <br />68<br />
Pole Figure Measurement<br />A Pole figure maps out the intensity over part of the spherical shell<br />2 stays fixed, th...
Pole figure example: Aligned ZnO wires<br />70<br />
Pole figures of ZnO<br /><br /><br />000l<br />71<br />
Few typical Diffractometer configurations <br />72<br />
Epi characterization<br /><ul><li>For this type of analysis typicaly the diffraction geometry if parallel beam.
The incident beam side is monochromated  and the type of monochromator depends on the needed resolution.
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Characterization Of Layered Structures By X Ray Diffraction Techniques

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Transcript of "Characterization Of Layered Structures By X Ray Diffraction Techniques"

  1. 1. X-Ray Scattering Methods for Characterization of Advanced Materials Workshop<br />Characterization of layered structures by x-ray diffraction techniques<br />Iuliana Cernatescu<br />PANalytical Inc.<br />Westborough, MA, USA<br />1<br />
  2. 2. Outline<br />Thin films definition and XRD applications<br />Reciprocal Space definition<br />Characterization of Epitaxial Layers<br />Characterization of Polycrystalline layers<br />Overview of typical optics and resolutions by sample types and target analysis<br />2<br />
  3. 3. Thin Film Definition<br />Nearly perfect epitaxy (thin film orientated to substrate parallel and perpendicular)<br />Imperfect epitaxy (thin film partially orientated to substrate parallel and perpendicular)<br />Textured polycrystalline (orientation unrelated to substrate but defined by growth)<br />Non-crystalline layers (no correlation beyond a bond length)<br />3<br />
  4. 4. Epitaxial Layers<br />Mismatch<br />Relaxation<br />Composition<br />In-Plane Epitaxy<br />Mosaic spread<br />Super-lattice period<br />Curvature<br />Off-Cut<br />Thickness<br />Density<br />Roughness<br />} XRR<br />
  5. 5. Polycrystalline Layers<br />Phase ID<br />Quantification<br />Unit Cell refinement<br />Residual stress<br />Crystallite size & micro-strain<br />Preferred orientation<br />Depth profiling of stress, phases, microstructure<br />Thickness<br />Density <br />Roughness<br />} XRR<br />
  6. 6. Amorphous Layers<br />Thickness <br />Density <br />Roughness<br />}XRR<br />
  7. 7. Reciprocal Space<br />1/<br />S<br />1/<br />1/<br />2<br /><br /><br /><br />7<br />
  8. 8. The Reciprocal Lattice from Planes<br /><ul><li>Create reciprocal lattice (RL), where each point represents a set of planes (hkl)</li></ul>-The points are generated from the RL origin where the vector, d*(hkl), from the origin to the RLP has the direction of the plane normal and length given by the reciprocal of the plane spacing. <br />002<br />112<br />1/d112<br />001<br />d*(112)<br />111<br />112<br />002<br />110<br />000<br />111<br />110<br />001<br />8<br />
  9. 9. Reciprocal Lattice and Scattering Vectors<br />Reciprocal lattice vector d*hkl<br />Length 1/d<br />Direction, normal to hkl planes<br />d*hkl<br />S<br />d*hkl<br />kH<br />k0<br />Incident beam vector, k0,<br />Length n/<br />Direction,  with respect to sample surface<br />k0<br /><br />2<br />000<br />kH<br />Scattered beam vector, kH,<br />Length n/ (user defined)<br />Direction, 2 with respect to k0<br />By rotating kH and kothe diffraction vector Scan be made to scan through reciprocal space.<br />When S = d*hklthen Bragg diffraction occurs<br />Diffraction vector, S,<br />S = kH – k0<br />S<br />9<br />
  10. 10. Scattering Vectors Related to a Real Experiment<br />Psi<br />Phi<br />source<br />Detector<br />S<br /><br />2<br />sample<br />10<br />
  11. 11. Reciprocal Lattice of a Single Crystal in 3D<br />115<br />-2-24<br /><ul><li>There are families of planes
  12. 12. All planes in the same family have the same length |d*|, but different directions
  13. 13. The family members have the same 3 indices (in different orders e.g. 400,040,004 etc)</li></ul>004<br />224<br />113<br />d*<br />| d*| = 1/dhkl<br />-440<br />440<br />Just a few points are shown for clarity<br />11<br />
  14. 14. Characterization of epitaxial Layers<br />12<br />
  15. 15. Epitaxial Samples in RS<br /><ul><li>We investigate the fine structure of individual reciprocal lattice spots</li></ul>115<br />004<br />224<br />113<br />“Reciprocal space map”<br />“Scan”<br />-440<br />440<br />This requires high resolution instrumentation<br />13<br />
  16. 16. Thin Layers and Multi-layers<br />115<br />224<br />004<br />113<br />-440<br /><ul><li>The reciprocal lattices of the crystals and the multilayer combine</li></ul>115<br />004<br />224<br />113<br />-440<br /><br />Fourier transform<br />Reflectivity is known as the 000 reflection<br />14<br />
  17. 17. RSM features bulk crystals<br />CTR = sample surface streak (and white radiation streak)<br />M = monochromator (or source) streak, parallel to diffracted beam<br />A = analyser (or detector) streak, parallel to tangent of Ewald sphere<br />S = Mosaic spread, curvature<br />(A)<br />(A)<br />S<br />S<br />M<br />(M)<br />CTR<br />CTR<br />15<br />
  18. 18. surface normal<br />high quality substrate -sharp peak<br />broadening normal to sample surface<br />thin layers<br />d spacing variation<br />broadening parallel to surface<br />mosaic structure <br />variable tilts (curvature or dislocations)<br />Shapes in RS<br />16<br />
  19. 19. layer<br />substrate<br />thick layer with grading and overall curvature<br />thin<br />layer<br />mosaic<br />layer<br />Examples Symmetric Reflections<br />17<br />
  20. 20. 4.8o<br />InGaAs tensile and compressive alternating multilayer on 001 InP substrate.<br />Bent multilayer sample<br />Samples with Bend or Tilt <br />18<br />
  21. 21. 19<br />Buffer Layer Structures<br />Relaxed Buffer layers as virtual substrates:e.g. Si/Ge on Si InGaAs on GaAs GaN on Sapphire<br />Substrate and surface layer lattice parameter calculations from reciprocal lattice coordinates (Bragg’s Law)<br />d*substrate<br />d*cap<br />d*layer<br />tilt<br />InP capping layer<br />Graded InxGa(1-x)As Buffer layer with dislocations<br />GaAs substrate<br />P. Kidd et al, J. Crystal growth, (1996) 169 649-659<br />
  22. 22. layer thickness<br />Tilt, thickness and lateral width<br />symmetric<br />asymmetric<br />Spread due to finite size effects<br />Range of tilts<br />In-plane<br />20<br />
  23. 23. Broadening effects on symmetric reflections<br />Omega broadening due to <br />Size effects<br />Omega broadening due to tilts<br />(s-x,sz)<br />(sx,sz)<br />(s-x,sz)<br />(sx,sz)<br /><br />1/L<br />000<br />000<br /><br />L<br />21<br />
  24. 24. Strained Layer<br />Q<br />at=aS<br />Layer<br />006<br />Substrate<br />L<br />004<br />224<br />-2-24<br />002<br />aS<br />S<br />fully <br />strained<br />220<br />110<br />Q||<br />22<br />
  25. 25. Relaxed Layer<br />Q<br />Layer<br />Substrate<br />006<br />at= aL<br />L<br />aL<br />004<br />224<br />-2-24<br />002<br />S<br />220<br />110<br />fully <br />relaxed<br />Q||<br /> at<br />23<br />
  26. 26. Relaxed layers RSM<br />24<br />
  27. 27. Scans in reciprocal space (1)<br />/2 scan<br />2’<br />’<br />25<br />
  28. 28. Scans in reciprocal space (2)<br />2’’<br />’’<br />26<br />
  29. 29. Scans in reciprocal space (3)<br />q varied<br />2’’’<br />’’’<br />27<br />
  30. 30. Scans in reciprocal space (1)<br />Rocking curve<br />2<br />’<br />28<br />
  31. 31. Scans in reciprocal space (2)<br />Rocking curve<br />2<br />’<br />29<br />
  32. 32. Scans in reciprocal space (3)<br />q constant<br />2<br />’’’<br />30<br />
  33. 33. Scans in reciprocal space (4)<br />2<br />’’’<br />31<br />
  34. 34. In-plane definition<br />Symmetrical<br />Diffraction <br />Gonio Scan<br />Grazing Incidence<br />Diffraction <br />2 theta scan<br />In-plane<br />Diffraction<br />Phi scan <br />Coupled scan<br />32<br />
  35. 35. In-Plane Diffraction<br />In-plane diffraction is a technique for measuring the crystal planes that are oriented perpendicular to the surface<br />| d*| = 1/dhkl<br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br />220<br />-2-20<br />33<br />
  36. 36. In-Plane Diffraction<br />2Theta/Omega scan<br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br />220<br />-2-20<br />34<br />
  37. 37. In-Plane Diffraction<br />2Theta/Omega scan<br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br />220<br />-2-20<br />35<br />
  38. 38. In-Plane Diffraction – phi scan <br />115<br />-2-24<br />224<br />004<br />113<br />d*<br />110<br />-1-10<br />220<br />-2-20<br />36<br />
  39. 39. RS Mapping<br />0<br />+<br />+<br /><br />-<br />+<br />2-<br />0<br />Omega offset<br />-<br />-<br />2Theta/omega<br />Reciprocal lattice view<br />Angular view<br />37<br />
  40. 40. Reciprocal Space Map<br />Qz<br />AlGaN/GaN MQW<br />GaN(0002)<br />Qx<br />38<br />
  41. 41. 12/1/2009<br /> Si (224) - 1D-mode with PIXcel<br /><ul><li>Reduced collecting time (1/10)
  42. 42. High dynamic range</li></ul>Si<br />SiGe<br />
  43. 43. X-ray diffraction - rocking curve<br />monochromator (collimator)<br />AlGaN layer<br />X-ray<br />source<br />Peak positions<br />/  d/d  composition,<br /> strain<br />f thickness<br />Peak shape thickness<br /> defects<br /> curvature<br />GaN <br /><br />Substrate<br />f<br />Layer<br />40<br />
  44. 44. Characterization of Polycrystalline layersspace<br />41<br />
  45. 45. 42<br />Definitions: Orientations of crystallites<br />Random orientation<br />Single crystal<br />Preferred orientation<br />
  46. 46. Polycrystalline random oriented<br />113<br />000<br />hkl <br />0 0 4<br />A sufficient number of randomly oriented crystals forms a reciprocal “lattice” of spherical shells<br />43<br />
  47. 47. Textured samples <br /><ul><li>Non uniform reciprocal lattice
  48. 48. Different intensities at different directions</li></ul>Spherical shell radius 1/dhkl<br />S<br />2<br />2<br />1/dhkl<br />S = 1/dhkl<br />44<br />
  49. 49. Characterization of Polycrystalline thin films<br />Phase ID<br />Phase ID with depth profiling<br />Residual stress<br />Residual stress with depth profiling<br />Texture analysis<br />45<br />
  50. 50. Symmetric 2Theta/Omega “powder” scans<br />Phase ID in polycrystalline samples<br />2Theta/Omega scan<br />scattering vector S<br />46<br />
  51. 51. Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />47<br />
  52. 52. Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />48<br />
  53. 53. Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />331<br />004<br />49<br />
  54. 54. Symmetric 2Theta/Omega “powder” scans<br />2Theta/Omega scan<br />111<br />220<br />311<br />422<br />331<br />004<br />511<br />50<br />
  55. 55. Symmetric scan for thin films<br />In the case of very thin films the scattering volume will become smaller and smaller as the symmetric scan progresses to higher angles. <br />The diffraction pattern of the substrate will dominate the diffractogram and could complicate the pattern analysis.<br />51<br />
  56. 56. Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />52<br />
  57. 57. Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />53<br />
  58. 58. Glancing Incidence Diffraction - 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />54<br />
  59. 59. Glancing Incidence - Diffraction 2Theta scan<br />Phase ID in thin film polycrystalline samples<br />55<br />
  60. 60. 56<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br /><br />ZnO<br />CIGS<br />0.45 deg<br />Mo<br />1.00 deg<br /><br />ZnO<br />ZnO<br />CIGS<br />Mo<br />2.00 deg<br /><br />ZnO<br />ZnO<br />CIGS<br />Mo<br />
  61. 61. 57<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br /><br />ZnO<br />CIGS<br />0.45 deg<br />Mo<br />1.00 deg<br /><br />ZnO<br />ZnO<br />CIGS<br />Mo<br />2.00 deg<br /><br />ZnO<br />ZnO<br />CIGS<br />Mo<br />
  62. 62. 58<br />GIXRD - Thin film depth profiling phase analysis<br />, Incident angle<br />ZnO<br />=0.45<br />CIGS<br />0.45 deg<br />Mo<br />1.00 deg<br />ZnO<br />=1<br />ZnO<br />CIGS<br />Mo<br />2.00 deg<br />ZnO<br />=2<br />ZnO<br />CIGS<br />Mo<br />
  63. 63. GIXRD in Reciprocal Space<br />powder<br />single crystal<br />Sampling only the random component of the studied sample.<br />59<br />
  64. 64. Residual Stress in Polycrystalline thin films<br />Non uniform reciprocal lattice<br />Different d-spacings at different directions<br />Polycrystalline components subjected to external mechanical stresses<br />Spherical shell distorted <br />(not to scale!)<br />S<br />2<br />2<br />1/dhklnot constant<br /><br />S = 1/dhkl<br /><br />One hkl reflection<br />60<br />
  65. 65. “Stress” Measurement<br />A stress measurement determines dhkl at a series of Psi positions<br />The sample is stepped to different  positions, 2 scan at each position to obtain peak position<br />Repeated for different  positions as required<br />Spherical shell distorted<br /><br />One hkl reflection<br />S<br />2<br />2<br />1/dhklvaries with position<br />61<br />
  66. 66. Classical Residual Stress<br />Single hkl<br /><br /><br /><br /><br /><br /><br />62<br />
  67. 67. Calssical Residual stress<br />Measure (very small) peak shifts as a function of the sample tilt angle ‘psi’<br />Plot d-spacing as a function of sin2(psi)<br />Fit straight line<br />63<br />
  68. 68. Multiple hkl residual stress analysis<br />Analysis<br />Determine peak positions<br />Calculate offsets<br />(w-q)=wfixed- ½ (2q)peak<br />Calculate sin2y values<br />y=(w-q)<br />Full range scan needed<br />Low 2q small sin2y (40 o2q sin2y ~0.11)<br />High 2q large sin2y (140 o2q sin2y ~0.87)<br />hkl<br />hkl<br />hkl<br />2q<br />w<br />64<br />
  69. 69. Stress depth gradient <br />Very small angle of incidence <br /> analyzing stress near surface<br />Coating<br />Substrate<br />65<br />
  70. 70. Stress depth gradient <br />Larger angle of incidence <br /> analyzing stress near surface AND deeper<br />Coating<br />Substrate<br />66<br />
  71. 71. Stress depth gradient <br />Largest angle of incidence <br /> analyzing average stress whole coating<br />Coating<br />Substrate<br />67<br />
  72. 72. Stress Gradient example - MgO on Glass <br />68<br />
  73. 73. Pole Figure Measurement<br />A Pole figure maps out the intensity over part of the spherical shell<br />2 stays fixed, the sample is scanned over all  at different  positions<br /><br /><br />One hkl reflection<br />S<br />2<br />2<br />69<br />
  74. 74. Pole figure example: Aligned ZnO wires<br />70<br />
  75. 75. Pole figures of ZnO<br /><br /><br />000l<br />71<br />
  76. 76. Few typical Diffractometer configurations <br />72<br />
  77. 77. Epi characterization<br /><ul><li>For this type of analysis typicaly the diffraction geometry if parallel beam.
  78. 78. The incident beam side is monochromated and the type of monochromator depends on the needed resolution.
  79. 79. For the diffracted beam side there are choises of TA, RC/open detector or line detector depending on the resolution needed.</li></ul>73<br />
  80. 80. Powders characterization<br /><ul><li>In the case of powder samples where we are scanning in a symmetrical manner Bragg-Brentano geometry is used due to its optical resolution.
  81. 81. Powder are often time analyzed with parallel beam, micor-spot beam, depending on the type of analysis required.</li></ul>74<br />
  82. 82. Configuration for Texture and stress analysis<br />Texture measurements require a point like source due to the tilting in Psi during the data collection of a pole figure.<br />In this case the tube was rotated to point focus in order to avoid defocusing error and have better intensity.<br />75<br />
  83. 83. Configuration for GIXRD, XRR and Residual Stress<br />Soller slits<br />Thin layers<br />X-ray tube<br />(line focus)<br />Sample<br />X-ray mirror<br />Parallel plate<br />collimator<br />Soller slits<br />Detector<br />Monochromator (optional)<br />76<br />
  84. 84. Summary [1]<br />crystal block size<br />residual stress<br />Perfect epitaxy<br />Nearly perfect epitaxy<br />Imperfect epitaxy<br />Textured polycrystalline <br />Perfect polycrystalline<br />Non-crystalline layers<br />defects<br />orientation<br />distortion<br />composition<br />relaxation<br />thickness<br />77<br />
  85. 85. Summary [2]<br />source<br />Detector<br />S<br /><br />2 <br />sample<br />An instrument<br />Provides X-rays<br />Aligns a sample<br />Detects diffraction pattern <br />A Material<br />Reciprocal “Lattice” Structure<br />An Experiment <br />Designed to suit the material<br />Designed to answer the question<br />78<br />

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