Power Cycling Capability Comparison of SiC-MOSFETs with SBD under Different Conduction Modes

Abstract:
Power cycling test(PCT) for SiC-MOSFETs with Schottky Barrier Diode(SBD) is conducted by the VDS(T) and VGE(th) mode under the same condition except the load current, respectively. The experimental results show that final failure mode of two methods are bond-wire cracking and lift-off, which is manifested by the rise of on-state voltage drop. However, For SiC MOSFETs, the lifetime under VDS(T) mode is much shorter than that under VGE(th) mode because of much higher load current. If only the lifetime and failure mode of this kind of power device need to be evaluated, the VDS(T) mode is the better choice especially for PCsec due to its higher heating current. The VGE(Th) mode is more suitable for calculating the junction temperature or the thermal resistance. The corresponding PCT method must be selected according to the actual working conditions of SiC-MOSFETs and the destination of the PCT.