Experimental Investigation of the Single Pulse Surge Current Ruggedness of the Body Diode of SiC Power MOSFETs

摘要

The single pulse surge current ruggedness of the body diode of commercially available SiC power planar and trench MOSFETs is analyzed. The surge current tests are conducted at different gate-source voltage (Vgs=0V/-5V) under different cooling environments (with or without the heat sink). Although the recommended turn-off voltage is usually -5V given in the datasheet, it does not help improve surge ruggedness enough. The experimental results show that the better cooling environment contributes little to the surge current capability of the body diode. In all devices under test (DUTs), the gate breakdown occurs first before the short circuit between the drain and source terminals. The surge I-V trajectory is plotted and analyzed based on resistances between the source and drain terminals. The I-V characteristic curve of the body diode is monitored and the shift caused by damage on p-n junction is observed.