3.3 kV 4H-SiC MOSFET with embeded hetero junction body diode for low switching loss

In this paper, we proposed a 3.3 kV class shielded hetero junction 4H-SiC MOSFET (SH-HJD MOSFET) device with improved switching loss and reverse recovery characteristics. The proposed SH-HJD MOSFET has a structure in which P+ poly-silicon is embedded between separated 4H-SiC P+ base. In the off-state, the depletion region created at the P+ base protects the P+ poly-silicon from high drain voltage and enables stable operation at high voltage. Moreover, the hetero junction between P+ poly-silicon and N drift acts as a unipolar diode and improves reverse recovery characteristics. Through TCAD simulation, SH-HJD MOSFET increased BFOM by 19.12% compared to conventional MOSFET (C-MOSFET), and the reverse recovery charge decreased by 93.7%. Finally, the switching loss of SH-HJD MOSFET was reduced by 61.86% compared to C-MOSFET.