Ultraviolet micro-Raman spectroscopy stress mapping of a 75-mm GaN-on-diamond wafer
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2016-05-23 |
| Journal | Applied Physics Letters |
| Authors | B. L. Hancock, Mohammad Nazari, Jonathan Anderson, E. L. Piner, Firooz Faili |
| Institutions | Georgia Institute of Technology, Woodruff Health Sciences Center |
| Citations | 30 |
Abstract
Section titled āAbstractāFull-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 Ā± 0.07 GPa at the free GaN surface compared to 0.23 Ā± 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.