Study of interface-trap and near-interface-state distribution in 4H-SiC MOS capacitor with full-distributed circuit model

Abstract In this research, by applying the full-distributed circuit model, the contribution of interface traps and near-interface states on electrical characteristics of 4H-SiC MOS capacitor were classified in a wide range of operation. By fitting the measured capacitance and conductance at a certain value of applied gate voltage when the frequency varied from 1 kHz to 1 MHz, the density of both near interface state and interface trap were determined. The results reveal that, at room temperature, the frequency dispersion of the capacitance in depletion condition is mainly caused by the contribution of interface traps. Nevertheless, in strong accumulation condition, near-interface states become dominant for the frequency dispersion of the capacitance. Furthermore, the full-distributed circuit model also successfully explained the electrical characteristics of the 4H-SiC MOS capacitor when operating at 500℃.