Ultraviolet micro-Raman spectroscopy stress mapping of a 75-mm GaN-on-diamond wafer

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 th...

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Bibliographic Details
Published in:Applied physics letters 2016-05, Vol.108 (21)
Main Authors: Hancock, B. L., Nazari, M., Anderson, J., Piner, E., Faili, F., Oh, S., Twitchen, D., Graham, S., Holtz, M.
Format: Article
Language:English
Subjects:
Applied physics
Chemical vapor deposition
Computer simulation
Dependence
Diamonds
Dislocation density
Mapping
Modulus of elasticity
Organic chemistry
Raman spectroscopy
Spectrum analysis
Stress relaxation
Tensile stress
Ultraviolet spectroscopy
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Summary: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.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4952596