Improvement of channel-carrier mobility in 4H-SiC MOSFETs correlated with passivation of very fast interface traps using sodium enhanced oxidation

Very fast interface traps have recently been suggested to be the main cause behind the rather poor inversion channel mobility in nitrided SiC metal-oxide-semiconductor-field-effect-transistors (MOSFETs). Using capacitance voltage analysis and conductance spectroscopy on metal oxide semiconductor capacitors, at cryogenic temperatures, we find that these fast traps are absent in oxides made by sodium enhanced oxidation, and high inversion channel-carrier mobility in MOSFETs made by sodium enhanced oxidation is observed.