High performance extended drain MOSFETs (EDMOSFETs) with metal field plate

We propose a structure for extended drain MOSFETs (EDMOSFETs) with a metal field plate separated from the gate electrode instead of the polysilicon field plate in conventional LDMOSFETs. The specific on-resistance is improved by applying a higher voltage to the field plate than the gate voltage because of the enhanced conductivity modulation, and the breakdown voltage of 280 V is not changed by the field plate voltage. When a voltage of 50 V is applied to the field plate, the specific on-resistance of a 280 V EDMOSFET is 17.63 mΩcm², which is lower than that of conventional LDMOSFETs by 11.8%. The performance of the EDMOSFETs is the best reported result in 280 V class lateral high voltage MOS devices