Analysis of power device failure under avalanche mode Conduction

This paper investigates the physics of device failure during avalanche for 1.2 kV SiC MOSFETs, silicon MOSFETs and silicon IGBTs. The impact of ambient temperature, initial conditions of the device prior to avalanche breakdown and the avalanche duration is explored for the different technologies. Two types of tests were conducted namely (i) constant avalanche duration with different peak avalanche currents and (ii) constant peak avalanche current with different avalanche durations. SiC MOSFETs are shown to be the most rugged technology followed by the silicon IGBT and the silicon MOSFET. The material properties of SiC suppress the triggering of the parasitic BJT that causes thermal runaway during avalanche.