A Novel 4H-SiC Trench MOSFET with Self-Adaptive Potential P-shield for Excellent Trade-off between Conduction Loss and Robustness

For the conventional 4H-SiC trench MOSFET, the trade-off among ON-state resistance(Ron), blocking robustness, and switching characteristics exists between the floating and grounded p-shield structures. In this work, an excellent balance is achieved by the proposed novel 4H-SiC trench MOSFET with self-adaptive potential p-shield(SAP-TMOS). The p-shield behaves as floating in the ON-state to suppress the depletion effect and reduce the on-resistance, while it is grounded in the OFF-state to enhance the blocking robustness and improve the switching performance. The proposed SAP-TMOS is demonstrated by 3D TCAD simulations and the potential modulation mechanism of the p-shield is analyzed. It achieves a breakdown voltage of 1557 V with reduced maximum gate oxide electric field(Eox) of 1.6 MV/cm, while featuring a low specific ON-state resistance(Ron,sp) of only 1.34 mΩ · cm2. The high-frequency figure of merit(HF-FOM) of 2746 mΩ · nC is obtained, which is 30.78% lower than that of the conventional grounded trench MOSFET. The proposed SAP-TMOS provides an excellent-balanced solution for high-voltage and high-frequency SiC power applications.