Hysteresis in transfer characteristics in 4H-SiC depletion/accumulation-mode MOSFETs

Hysteresis in room-temperature transfer characteristics between forward (pinch-off voltage, V/sub P/=-15 V) and reverse gate voltage sweeps (V/sub P/=7 V) in n-channel depletion/accumulation-mode 4H-SiC MOSFETs is reported. Transfer characteristics exhibit a parallel shift toward negative voltages depending,on the starting gate voltage and direction of the sweep. The hysteresis and shift in transfer characteristics are related to changes in effective fixed-oxide charge resulting from changes in interface trap occupancy. Interface trap occupancy changes depending on the magnitude of the starting gate voltage and the direction of gate-voltage sweep. At high temperatures, the hysteresis between forward and reverse gate voltage sweep decreases.