A split gate double-channel asymmetric SiC trench MOSFET for improved gate oxide reliability and dynamic characteristics

A split-gate double-channel asymmetric SiC trench MOSFET (SGDC-ATMOS) is proposed in this work. Besides a P⁺ shielded region covering the bottom of the trench, a charge balance effect caused by the split gate further reduces the maximum gate oxide electric field (E_mox) around the trench, which effectively improves the reliability of the SGDC structure. Additionally, the excellent capacitance characteristics is achieved by varying the length of the P⁺ shielded region on the right side of the trench. The SGDC structure ensures better current conduction capability by adopting a double conduction channel. Furthermore, the SGDC structure also introduces a current spreading layer to alleviate the junction field-effect transistor (JFET) effect. Simulations demonstrate that, compared with the conventional asymmetric trench MOSFET (C-ATMOS), the SGDC structure shows a 31.5% reduction in the E_mox, a 98.4% reduction in the gate-drain capacitance, and a 5% reduction in specific on-resistance, which demonstrates superior gate oxide reliability and dynamic characteristics, making it better suited for the high-performance and low power-loss applications.