A novel SiC high-k superjunction power MOSFET integrated Schottky barrier diode with improved forward and reverse performance

Abstract

Abstract A new SiC superjunction power MOSFET device using high-k insulator and p-type pillar with an integrated Schottky barrier diode (Hk-SJ-SBD MOSFET) is proposed, and has been compared with the SiC high-k MOSFET (Hk MOSFET), SiC superjuction MOSFET (SJ MOSFET) and the conventional SiC MOSFET in this article. In the proposed SiC Hk-SJ-SBD MOSFET, under the combined action of the p-type region and the Hk dielectric layer in the drift region, the concentration of the N-drift region and the current spreading layer can be increased to achieve an ultra-low specific on-resistance (R on,sp). The integrated Schottky barrier diode (SBD) also greatly improves the reverse recovery performance of the device. TCAD simulation results indicate that the R on,sp of the proposed SiC Hk-SJ-SBD MOSFET is 0.67 mΩ·cm2 with a 2240 V breakdown voltage (BV), which is more than 72.4%, 23%, 5.6% lower than that of the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET with the 1950, 2220, and 2220 V BV, respectively. The reverse recovery time and reverse recovery charge of the proposed MOSFET is 16 ns and18 nC, which are greatly reduced by more than 74% and 94% in comparison with those of all the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET, due to the integrated SBD in the proposed MOSFET. And the trade-off relationship between the R on,sp and the BV is also significantly improved compared with that of the conventional MOSFET, Hk MOSFET and SJ MOSFET as well as the MOSFETs in other previous literature, respectively. In addition, compared with conventional SJ SiC MOSFET, the proposed SiC MOSFET has better immunity to charge imbalance, which may bring great application prospects.