The role played in the improvement of the SiO2/SiC interface by a thin SiO2 film thermally grown prior to oxide film deposition

Abstract

To minimize electrical degradation from thermal oxidation of 4H-SiC, a thin and stoichiometric SiO2 film was thermally grown, monitored by X-ray photoelectron spectroscopy. To obtain thicker films, SiO2 was deposited by sputtering. Reduction in the flatband voltage was observed when compared to SiO2 films thermally grown or deposited directly on 4H-SiC. Post-deposition annealing in Ar reduced the flatband voltage of the samples but induced an electrical degradation in the SiO2/4H-SiC interface. Nuclear reaction analyzes proved that the thin film thermally grown was not stable during the annealing, exchanging O atoms with the deposited film and with the gaseous ambient.