Body doping dependence of field-effect mobility in both n- and p-channel 4H-SiC metal-oxide-semiconductor field-effect transistors with nitrided gate oxides

Abstract

Abstract Both n- and p-channel SiC MOSFETs, the gate oxides of which were annealed in NO, with various body doping concentrations were fabricated. Despite the large difference in bulk mobility between electrons (1020 cm 2 V −1 s −1 ) and holes (95 cm 2 V −1 s −1 ), the maximum field-effect mobility in heavily-doped (∼5 × 10 17 cm −3 ) MOSFETs was 10.3 cm 2 V −1 s −1 for the n-channel and 7.5 cm 2 V −1 s −1 for the p-channel devices. The measurements using body bias revealed that the field-effect mobility in both n- and p-channel SiC MOSFETs is dominated by the effective normal field rather than the body doping.