Thermally oxidized GaN film for use as gate insulators

Abstract
The structural and electrical characteristics of a thermally grown gallium oxide on GaN films were investigated. A furnace oxidation at 850 °C for 12 h resulted in the formation of monoclinic β-Ga2O3, 88 nm in thickness. From the I–V measurements of the metal–oxide–semiconductor (MOS) structure, the breakdown field strength (EBD) was found to be 3.85±0.32 MV cm−1. Under gate voltage sweep, C–V hysteresis was observed due to the oxide charge trap. By comparing the ideal and experimental C–V curves, the oxide charge density (Nf) was calculated to be 6.77×1011 cm−2. These results suggest that the thermally grown Ga2O3 is suitable for gate dielectric applications of power MOS field-effect transistors.