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This study investigates the texture variations in a 6” wafer, utilizing data from four detectors (GE1, GE2, GE3, GE4) that were scanned every millimeter. Results indicate strong {220} reflections in GE3 and GE4, contrasting with weaker readings in GE1 and GE2, which also reveal contributions from {113} and {133} planes. The study suggests a connection between sample geometry, specifically curvature, and texture loss. Phase fraction analysis indicates a 2-4% presence of hcp, with implications for understanding phase transitions and texture correlations.
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APS8_14 M.J. Kramer July 1, 2012
70 mm strip from center of the 6” wafer • Data taken every 1 mm • 4 detectors show some variation in texture GE3 GE4 GE2 GE1
GE 3 and GE4 show a very strong {220} while GE1 and GE2 have a weaker {220} and more contributions from {113} and {133}
The {113} and {133} are only a few degrees from being strong scattering in this geometry. • Suggests something about the sample geometry, possibly curvature of the sample, since GE1 and GE2 are both below the horizon and GE3 and GE4 are above. • Also (112) only 19.5° from (111)
Rietveld fitting provides a clearer idea of the reflections of the 2nd Ag phase. • Quantify the phase fraction via fcc (220) to the hcp peak • Roughly 2-4% • Broadening of the hcp peak and overlap
GE4 GE4 • Indication of intercalations driving the phase transition? • Direct correlation between loss of the texture and disappearance of the hcp phase Disordered phase Discrete phase
GE2 • Slightly different orientation provides a different perspective GE2
GE1 • GE doesn’t show the disordered region • Loss hcp still correlates with loss of (220) texturing • Also the (220) texture is strong when hcp diffuse is weak
GE1 Proposed hcp model doesn’t get this right
[111] • [-110] 11-2 1-10 11-2 111
[001] 20° tilt from [001]
Remove corner atoms • 2x2x2 unit cell • Shows the same layers as the hcp when viewed perpendicular 11-2 111
The 2x2x2 seems to show the hcp but a,b stacking fails to connect rings correctly
Isolated a, b layer in the 2x2x2 • Note when isolating the two layers, packing is not dense enough.
Using the rhombohedral distortion SG 160 • Get a bit better fitting • Still have trouble with the side peak on the fcc (200)