Significantly improved channel mobility of 202 cm(2)/Vs has been achieved in a normally-off 4H-SiC accumulation-mode MOSFET (ACCUFET) by using a two layer stacked gate oxide. The stacked gate oxide comprises a thin thermal oxide and a non-doped silicate glass (NSG) deposited over it. This stacked gate oxide can form a MOS interface containing a smaller interface state density (Dit) than that of a MOS interface formed by a thermally grown oxide only. The channel mobility of an ACCUFET with the thermal gate oxide only was 114 cm(2)/Vs.