A new power W-gated trench MOSFET (WMOSFET) with high switching performance

A new power Trench MOSFET with W-shaped gate structure (WMOSFET) that demonstrates a significant reduction in gate-drain charge Qgd, a low on-resistance, and good production process margin is reported. The gate is formed using a thicker oxide at the bottom of the trench that is self-aligned to the P-body/N-epi junction. Fabricated 35 V N-channel devices exhibit a Rdson*Qgd Figure of Merit of 12.5 m/spl Omega/.nC with V/sub GS/=10V and V/sub DD/=15V. Experimental data of devices fabricated using LOCOS and Sub Atmospheric CVD (SACVD) processes to form the thicker oxide layer along with simulation results are presented.