Impact of Embedding Schottky Barrier Diodes into 3.3 kV and 6.5 kV SiC MOSFETs

External Schottky barrier diodes (SBDs) used as free-wheel diodes should be larger in higher voltage devices to avoid bipolar degradation consequent on current conduction of body diodes in SiC MOSFETs. By embedding an external SBD into an SiC MOSFET, we achieved compact 3.3 kV and 6.5 kV SiC MOSFETs that are free from bipolar degradation. The active area of the 3.3 kV/6.5 kV samples is only about a half/quarter of the total active area of a conventional MOSFET and a coupled external SBD.