SiC gate-controlled bipolar field effect composite transistor with polysilicon region for improving on-state current

Abstract

A novel silicon carbide gate-controlled bipolar field effect composite transistor with polysilicon region (SiC GCBTP) is proposed. Different from the traditional electrode connection mode of SiC vertical diffused MOS (VDMOS), the P+ region of P-well is connected with the gate in SiC GCBTP, and the polysilicon region is added between the P+ region and the gate. By this method, additional minority carriers can be injected into the drift region at on-state, and the distribution of minority carriers in the drift region will be optimized, so the on-state current is increased. In terms of static characteristics, it has the same high breakdown voltage (811 V) as SiC VDMOS whose length of drift is 5.5 μm. The on-state current of SiC GCBTP is 2.47 × 10−3 A/μm (V G = 10 V, V D = 10 V) which is 5.7 times of that of SiC IGBT and 36.4 times of that of SiC VDMOS. In terms of dynamic characteristics, the turn-on time of SiC GCBTP is only 0.425 ns. And the turn-off time of SiC GCBTP is similar to that of SIC insulated gate bipolar transistor (IGBT), which is 114.72 ns.