Tunable trench gate power MOSFET: a feasible superjunction device and process technology

For power semiconductor MOSFET devices, the oxide-bypassed structure utilizes the oxide thickness control in fabrication instead of the complicated doping control in translating the unipolar on-resistance R_ON versus the blocking voltage V_BR tradeoff limit beyond the conventional unipolar silicon limit. The structure also provides the option to utilize an additional bias voltage to compensate possible process variations in order to enhance the breakdown voltage. This paper describes the structure, fabrication process and the laboratory results on the tunable oxide-bypassed trench gate power MOSFET. The technology is proven to be feasible in making superjunction MOSFET devices for power electronic applications.