Ultraviolet micro-Raman spectroscopy stress mapping of a 75-mm GaN-on-diamond wafer
Abstract
Full-wafer stress mapping is accomplished using visible and ultraviolet (UV) micro-Raman spectroscopy of a 730-nm thick GaN layer integrated with diamond grown by chemical vapor deposition. The UV measurements taken from both sides of the wafer reveal a higher tensile stress of 0.86 ± 0.07 GPa at the free GaN surface compared to 0.23 ± 0.06 GPa from the GaN/diamond interface, each with good cross-wafer uniformity. Factors influencing the overall stress and stress gradient are understood based on relaxation from dislocations in the GaN which vary in density along the growth direction. Simulations incorporating a model for stress relaxation in the GaN elastic modulus adequately describe the observed dependence.
- Publication:
-
Applied Physics Letters
- Pub Date:
- May 2016
- DOI:
- 10.1063/1.4952596
- Bibcode:
- 2016ApPhL.108u1901H