Verification of near-interface traps by electrical measurements on 4H-SiC n-channel MOSFETs

4H-SiC n-channel lateral MOSFETs were manufactured and characterized electrically by current-voltage measurements and by numerical simulation. To describe the observed electrical characteristics of the SiC MOSFETs, Near-Interface Traps (NIT) and mobility degradation models were included in the simulation. The main finding of the simulation is that two models for the NIT states in the upper part of the SiC bandgap are able to describe the electrical data equally well. In one of them, acceptor-like traps and fixed charge are considered while in a newly developed one, donor-like traps are taken into account also.