A novel 4H-SiC trench MOSFET with double shielding structures and ultralow gate-drain charge

A new ultralow gate–drain charge(Q;) 4 H-SiC trench MOSFET is presented and its mechanism is investigated by simulation. The novel MOSFET features double shielding structures（DS-MOS）: one is the grounded split gate（SG）, the other is the P+shielding region（PSR）. Both the SG and the PSR reduce the coupling effect between the gate and the drain, and transform the most part of the gate–drain capacitance(C;) into the gate–source capacitance(C;) and drain–source capacitance(C;) in series.Thus the C;is reduced and the proposed DS-MOS obtains ultralow Q;. Compared with the double-trench MOSFET（DT-MOS）and the conventional trench MOSFET（CT-MOS）, the proposed DS-MOS decreases the Q;by 85% and 81%, respectively.Moreover, the figure of merit（FOM）, defined as the product of specific on-resistance(R;) and Q;(R;Q;), is reduced by 84% and 81%, respectively.