On the subthreshold measurements of SIC MOSFETs

Reported here are subthreshold measurements on n-channel 6H-SiC MOSFETs over a range of temperatures. A simple theoretical model is presented to explain their general form. It is shown that the temperature dependence of the subthreshold current indicates a high density of electronic states at or near the SiC-SiO₂ interface. These states are negatively charged when occupied (acceptor-like), and emit their trapped electrons at elevated temperatures. They are believed to be responsible for the observed shift in the subthreshold characteristics at higher temperatures.