Interface states and field-effect mobility in 6H-SiC MOS transistors

Silicon carbide MOSFETs exhibit a large degradation of field-effect mobility relative to the bulk-carrier mobility in silicon carbide. in this work, we relate the transconductance and field-effect mobility of SiC UMOS transistors to carrier localization in disorder-induced band-tail states that arise as a consequence of potential fluctuations in inversion layers. A semiclassical model for the density of localized states below the conduction band edge predicts the general trends in the gate-bias and temperature dependence of the drain current observed in experimental devices.