Bowing of thick GaN layers grown by HVPE using ELOG

Published in:
phys. stat. sol. (c)3, 6 (2006) 1466-1470.
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Abstract:
Intrinsic stress in GaN layers grown by HVPE on sapphire substrates results in wafer breakage for thicknesses exceeding 40 µm. Using ELOG 180 µm GaN can be grown on 2 inch. The bowing of the wafers caused by extrinsic stress due to the different thermal expansion is not affected by ELOG. Using WSiN as mask material a 600 µm thick free-standing 2 inch GaN layer has been obtained by exploiting the shear forces occurring during cooling after growth for separation from the ELOG template.

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