Device-quality GaN–dielectric interfaces by 300 °C remote plasma processing

Abstract

In previous studies, device-quality Si–SiO 2 interfaces and dielectric bulk films (SiO 2) were prepared using a two-step process; (i) remote plasma-assisted oxidation (RPAO) to form a superficially interfacial oxide (∼0.6 nm) and (ii) remote plasma enhanced chemical vapor deposition (RPECVD) to deposit the oxide film. The same approach has been applied to GaN–SiO 2 system. Low-temperature (300 °C) remote N 2/He plasma cleaning of the GaN surface, and the kinetics of GaN oxidation using RPAO process and subcutaneous oxidation during the SiO 2 deposition using an RPECVD process have been investigated from analysis of on-line Auger electron spectroscopy (AES) features associated N and O. Compared to single-step SiO 2 deposition, significantly reduced defect state densities are obtained at the GaN–dielectric interfaces by independent control of GaN–GaO x ( x∼1.5) interface formation by RPAO, and SiO 2 deposition by RPECVD.