Rapid thermal annealing effects on radio-frequency magnetron-sputtered P-type GaN thin films and Al/P-type GaN Schottky diodes

Abstract

In this article, we report the effects of RTA on Mg-diffused GaN thin films and Al/Mg-diffused GaN Schottky diodes. After Mg-diffusion process, the samples were exposed to RTA treatment in the temperature from 800 to 900°C. The samples were studied by variable temperature Hall effect measurements, and PL spectroscopy. The reduced resistivity by higher RTA temperature is due to the increased activated acceptor. Evidence, showed that both near-band-edge emission and deep level luminescent in PL spectrum could be all enhanced by raising the RTA temperature. Considering the Al/Mg-diffused GaN Schottky diodes, the higher RTA temperature resulting in the superior forward conduction characteristics are suggested to be due to the more concentrations of hole and lower resisivity of the GaN thin film. However, the greater reverse leakage current and lower breakdown voltage were deduced to be the creation formation of Ga-Al compounds at the metal-semiconductor interface.