Electrical characteristics of temperature‐difference liquid phase deposited SiO₂ on GaN with (NH₄)₂S_x treatment

Abstract

The characteristics of a SiO2 film grown on (NH4)2Sx treated GaN by temperature‐difference liquid phase deposition were investigated. Hydrofluorosilicic acid and boric acid were used as deposition solutions. For GaN without the (NH4)2Sx treatment, an Al/SiO2/GaN MOS diode shows poor electrical characteristics due to the native oxides existing at the interface. With (NH4)2Sx treatment of GaN, a stable sulfide‐terminated surface is obtained and the leakage current density of SiO2/GaN is improved from 6.15 × 10–4 A/cm2 to 2.08 × 10–5 A/cm2 at the electric field of 2 MV/cm. The effective oxide charges decrease from 6.09 × 1011 C/cm2 to 2.23 × 1011 C/cm2. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)