Narrow Gate Trench Power MOSFETs with Stepped Field Plate and Polysilicon Bridge

A new narrow gate (NG) trench MOSFET with stepped field plate (SFP) and polysilicon bridge (PB), named NSP-MOSFET, is proposed and discussed in this paper. The SFP can smooth electric field profile along trench, thus improving doping concentration of epitaxial layer and reducing specific on-resistance (R ON,SP ). The NG reduces parasitic gate capacitance and gate charge (Q G ). In addition, the PB can partly offset the increase of internal gate resistance induced by the NG. T-CAD simulations are performed to evaluations of fundamental performances. Benefiting from structural improvements, the proposed device obtains about 22 % and 9.5 % reductions in R ON,SP ×Q G compared with conventional trench MOSFET and SFP trench MOSFET, respectively.