In this article, a novel 1200 V SiC super-junction (SJ) MOSFET with a partially widened pillar structure is proposed and investigated by using the two-dimensional numerical simulation tool. Based on the SiC SJ MOSFET structure, a partially widened P-region is added at the SJ pillar region to improve the short-circuit (SC) ability. After investigating the position and doping concentration of the widened P-region, an optimal structure is determined. From the simulation results, the SC withstand times (SCWT) of the conventional trench MOSFET (CT-MOSFET), the SJ MOSFET, and the proposed structure at 800 V DC bus voltage are 15 μs, 17 μs, and 24 μs, respectively. The SCWT of the proposed structure increased by 60 % and 41.2 % in comparison with that of the other two structures. The main reason for the proposed structure with an enhanced SC capability is related to the effective suppression of saturation current at the high DC bias conditions by using a modulated P-pillar region. Meanwhile, a good Baliga’s FOM (BV 2/R on) also can be achieved in the proposed structure due to the advantage of the SJ structure. In addition, the fabrication technology of the proposed structure is compatible with the standard epitaxy growth method used in the SJ MOSFET. As a result, the SJ structure with this feasible optimization skill presents an effect on improving the SC reliability of the SiC SJ MOSFET without the degeneration of the Baliga’s FOM.

In this paper, a novel 1200 V SiC trench MOSFET with a laterally widened P-shield region (LW-MOSFET) is presented by using the two-dimensional numerical simulation. Compared with the conventional trench MOSFET (CT-MOSFET), the LW-MOSFET demonstrates an effective enhancement on the short-circuit (SC) reliability and the optimization of static performance simultaneously. According to the simulation results, the SC withstand time (SCWT) of the LW-MOSFET at 600 V DC bus voltage can reach 8 μs, while that of the CT-MOSFET is only 3 μs at the same conditions. The main reason is that the laterally widened P-shield region can help to suppress the saturation current and mitigate the huge current accumulation near the trench area, leading to an enhancement of the SC reliability. Moreover, the Baliga’s FOM of the proposed structure is improved by 45.7%, which benefits from the higher breakdown voltage (BV) and the lower specific on-state resistance (Ron, sp) by using the optimized structure. The advantage of static performance is related to the local charge balance behavior provided by the laterally widened P-shield region, which helps to use a higher doped current spread layer (CSL) without bringing a degeneration of BV.