Electrical characteristics of temperature-difference liquid phase deposited SiO₂on GaN with (NH₄)₂S_xtreatment

The characteristics of a SiO(2) film grown on (NH(4))(2)S(x) treated GaN by temperature-difference liquid phase deposition were investigated. Hydrofluorosilicic acid and boric acid were used as deposition solutions. For GaN without the (NH(4))(2)S(x) treatment, an Al/SiO(2)/GaN MOS diode shows poor electrical characteristics due to the native oxides existing at the interface. With (NH(4))(2)S(x) treatment of GaN, a stable sulfide-terminated surface is obtained and the leakage current density of SiO(2)/GaN is improved from 6.15 x 10(-4) A/cm(2) to 2.08 x 10(-5) A/cm(2) at the electric field of 2 MV/cm. The effective oxide charges decrease from 6.09 x 10(11) C/cm(2) to 2.23 x 10(11) C/cm(2). (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim