Short-circuit capability of 1200V SiC MOSFET and JFET for fault protection

The short-circuit capability of power switches is crucial for the fault protection. In this paper, 1200V SiC MOSFET and normally-off SiC JFET have been characterized and their short-circuit capabilities have been studied and analyzed at 400V DC bus voltage. Due to different physics in the channels, SiC MOSFET and SiC JFET show different types of temperature coefficient. During the short-circuit operation, the saturation current, Isat, of SiC MOSFET increases for several microseconds before the gentle decreasing while that of SiC JFET decreases drastically from the very beginning. The SiC MOSFETs failed after short-circuit operations of 80µs and 50µs at 10V and 15V gate bias respectively while the SiC JFET could survive a short-circuit time more than 1.4msec.