Deep traps and thermal measurements on AlGaN/GaN on Si transistors

AlGaN/GaN structures grown on Si substrates by metal organic chemical vapor deposition have been processed into high power transistors with maximum input power density of 12 W/mm. The transistor showed low concentration of bulk electron traps in the GaN buffer and of interfacial traps at the AlGaN/GaN interface. A new version of contactless thermography method based on microcathodoluminescence spectra for transistors under operation was shown to produce similar results to more established techniques based on measurements of the E2(high) phonon frequency shift in the GaN buffer and of the TO phonons in the Si substrate. The results of temperature measurements are in good agreement with modeling results. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3605304]