Analysis of SiC MOSFET dI/dt and its temperature dependence

A change regulation of variation in drain current (dI(D)/dt) of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) and their temperature dependencies are examined. Experimental results show that the magnitude of turn-off dI(D)/dt decreases with temperature and turn-on dI(D)/dt increases with increasing temperature. Further analysis shows that turn-on dI(D)/dt is better than turn-off dI(D)/dt in terms of temperature dependency and exhibits good linearity. This behaviour results from the positive temperature coefficient of the intrinsic carrier concentration and the negative temperature coefficient of the effective mobility of the electrons in the SiC MOSFET. Other factors that affect the temperature dependency of dI(D)/dt, such as supply voltage, load current, and gate resistance, are also discussed. A temperature-based analytical model of dI(D)/dt for the SiC MOSFET is derived using fundamental device physics equations. The calculations generally fit the measurements well. These results are beneficial since they provide a potential approach for junction temperature estimation in the SiC MOSFET. In SiC MOSFET-based practical applications, if turn-on dI(D)/dt is sensed, then the junction temperature can be derived from the relationship curve of turn-on dI(D)/dt versus temperature drawn experimentally in advance.