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

A new ultralow gate–drain charge(QGD) 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(CGD) into the gate–source capacitance(CGS) and drain–source capacitance(CDS) in series.Thus the CGD is reduced and the proposed DS-MOS obtains ultralow QGD. Compared with the double-trench MOSFET（DT-MOS）and the conventional trench MOSFET（CT-MOS）, the proposed DS-MOS decreases the QGD by 85% and 81%, respectively.Moreover, the figure of merit（FOM）, defined as the product of specific on-resistance(Ron, sp) and QGD(Ron, spQGD), is reduced by 84% and 81%, respectively.