Characterization of Near Conduction Band SiC/SiO2 Interface Traps in Commercial 4H-SiC Power MOSFETs

It is well known that the high density of interface traps (D it ) near the conduction band (CB) edge limits the net inversion layer charge in the conduction band of a 4H-SiC/SiO 2 MOSFET in strong inversion. Measurements at cryogenic temperatures are necessary to study the presence of interface trap density (D it ) up to the CB edge. In our study, we extracted the threshold voltage (V T ) from cryogenic (10 K) to high temperature (500 K) and calculated the V T shift which is a measure of interface trapped negative charge (∆Q it ). This shift in negative charge is used to estimate a relative magnitude of D it near the CB edge. The higher the value of ∆V T , the higher the D it for a given sample.