A Sidewall Enhanced Trench Poly-Si/SiC Heterojunction Diode with Energy Barrier Height Control Technology

Silicon carbide power diodes are widely used in various power electronic systems due to their low losses. In the conventional SiC Schottky diodes, the forward voltage drops mainly depends on the work function of the anode metal material, which brings constraints to the design of SiC Schottky diodes. For the proposed poly-Si/SiC heterojunction diode (HJD), the barrier height and forward voltage drop can be optimized by adjusting the polysilicon doping type and concentration. And the trade-off relationship between the on-state conduction loss and off-state loss (leakage current) also can be improved according to different applications. In this paper, a novel sidewall enhanced trench HJD is proposed to achieve extremely low leakage current under the premise of high forward current density and low on-voltage drop, which brings a new design method for the SiC power diodes.