摘要

A novel 4H-SiC MESFETstructure with stepped source field plate (SSFP-MESFET) is proposed. The stepped source field plate consists of upper and lower parts. Two addition field peaks formed at both upper and lower source field plate edges weaken the equipotential lines crowding at the gate edge and enhance the breakdown voltage. The effect of the SSFP on breakdown voltage (V-BR), saturation current and RF characteristics are detailed investigated by 2D numerical simulation. The simulated results show that obvious improvement can be obtained for the SSFP-MESEFT compared to the conventional MESFET structure (C-MESFET). To be specific, the V-BR of the SSFP-MESFET is enhanced from 72V to 150V which means more than 108% improvement is achieved and the output power density (P-max) of is about 110% larger. Meanwhile, due to the depletion layer formed under the stepped source field, the gate-drain capacitance of the SSFP-MESFET structure is 23% smaller.