Study of SiC vertical JFET behavior during unclamped inductive switching

Excellent physical and electrical properties of SiC material make SiC JFETs extremely attractive for high power density, high temperature and high frequency power applications. With increased switching speed, a stable operation capability of the devices under unclamped inductive switching (UIS) conditions is critical for the reliable operation of power switching systems. In this work, the behaviors of 1.2kV SiC normally-on vertical JFETs under UIS conditions are investigated by performing UIS tests. A record high energy density of 9,407mJ/cm
²
dissipated in the device during UIS is measured. Physics-based mixed-mode electro-thermal device simulations are also performed to predict the maximum device temperatures during UIS and to understand JFET failure modes.