A Novel SONOS Gate Power MOSFET With Excellent UIS Capability

A novel silicon-oxide-nitride-oxide-silicon gate power MOSFET is proposed and experimentally demonstrated. In the novel device, the doping concentration of the p-body is increased by an order of magnitude compared to that of the conventional power MOSFET. However, the positive shift of the threshold voltage due to the heavily doped p-body is fully compensated by the positive fixed charges preprogrammed in the silicon nitride of the oxide-nitride-oxide gate dielectric. As a result, a normal threshold voltage can be obtained, and the avalanche energy absorption of the novel device at unclamped inductive switching is 5.2 times that of the conventional power MOSFET.