The authors have applied contactless electroreflectance (CER) spectroscopy to study the epi readiness of -plane GaN substrates obtained by the ammonothermal method. It has been clearly observed that the CER resonance, which is related to the energy gap transition, appears for samples with a well-polished surface. The sharpness of this resonance is directly related to the surface quality. The broadening of energy gap transition can be used as a parameter to quantify the surface quality. For samples polished with optimal conditions, this broadening is close to the broadening observed for the cleaved GaN surface with -plane orientation (150–190 vs 135 meV). The quality of the polishing process can be evaluated by analyzing the ratio, where corresponds to an excellent polishing process. In the authors’ case, this ratio has been determined to be close to 1 for well-polished samples.
Application of contactless electroreflectance to study the epi readiness of -plane GaN substrates obtained by ammonothermal method
R. Kudrawiec, R. Kucharski, M. Rudziński, M. Zając, J. Misiewicz, W. Strupiński, R. Doradziński, R. Dwiliński; Application of contactless electroreflectance to study the epi readiness of -plane GaN substrates obtained by ammonothermal method. J. Vac. Sci. Technol. A 1 November 2010; 28 (6): L18–L21. https://doi.org/10.1116/1.3504359
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