Analysis of SiC MOSFET dI/dt and its temperature dependence

摘要

An analysis of variation of drain current (dI_D/dt) of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) in turn-on and turn-off under different temperatures has been performed in this paper. It is shown that the magnitude of turn-off dI_D/dt is temperature dependent and decreases with temperature with a fixed supply voltage, load current and gate resistance. While, the turn-on dI_D/dt increases with increasing temperature. It has been demonstrated that the temperature dependency of variation of drain current results from the positive temperature dependency of the intrinsic carrier concentration and the negative temperature dependency of the effective mobility of the electrons in SiC MOSFET. The temperature dependency of dI_D/dt is strongly correlated with gate resistance, which varies with different gate resistors. In addition, the effects of supply voltage and load current have also been discussed. The temperature dependence characterization of variation of drain current for SiC MOSFETs is derived. The comparisons between the calculated results using the derived model and the measurements show the calculations generally fit the measurements well. These results are beneficial in condition monitoring of power devices, operating temperature and device reliability.