Ultraviolet Micro-Raman Spectroscopy Stress Mapping of a 75-mm GaN-on-Diamond Wafer




Hancock, Bobby Logan
Nazari, Mohammad
Anderson, J.
Piner, Edwin L.
Faili, F.
Oh, S.
Twitchen, D.
Graham, S.
Holtz, Mark

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AIP Publishing


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.



ultraviolet micro-raman spectroscopy, diamond, chemical vapor deposition, Physics


Hancock, B. L., Nazari, M., Anderson, J., Piner, E., Faili, F., Oh, S., Twitchen, D., Graham, S. & Holtz, M. (2016). Ultraviolet micro-Raman spectroscopy stress mapping of a 75-mm GaN-on-diamond wafer. Applied Physics Letters, 108(3), 211901.


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