Improved oxide field and switching performance obtained in a CoolSiCTM trench MOSFET by incorporating the superjunction concept

Abstract

The superjunction concept is incorporated in a CoolSiC trench MOSFET structure to investigate its potential on static and dynamic characteristics using two-dimensional simulations. The effects of device topology on the breakdown voltage and specific on resistance (Rsp,on) are studied. Optimized results show an improvement in the breakdown voltage by 34% and Rsp,on by 30%, compared with the standard CoolSiC MOSFET structure. Furthermore, a marginal improvement in the off state trench corner electric field is obtained. The switching behavior using a clamped inductive circuit showed improved turn on and turn off losses at 900 V, 4 A. After the addition of stray inductance, we observed a less than 0.2 V shift in the gate voltage waveform. Simulation results indicate that the proposed structure has shown improved device characteristics and enhanced turn off performance owing to a reduction in gate charge (Qg) and Miller capacitance.