Improved 4H–SiC MESFET with double source field plate structures

An improved 4H–SiC power MESFET with double source field plates (DSFP) for high-power applications is proposed (DSFP-MESFET). The DSFP structure significantly modifies the electric field in the drift layer. The influence of the DSFP structure on saturation current, breakdown voltage (Vb), and small-signal characteristics of the DSFP-MESFET were studied by numerical device simulation. The Vb of 359 V is obtained for the DSFP-MESFET compared to 301 V of the conventional source field plate MESFET (LSFP-MESFET). Hence, the maximum output power density of 24.7 and 21.8 W/mm are achieved for the DSFP-MESFET and LSFP-MESFET, respectively, which means 13% improvement for the proposed device. Also, the cut-off frequency (fT) of 24.5 and the maximum oscillation frequency (fmax) of 89.1 GHz for the 4H–SiC DSFP-MESFET are obtained compared to 23.1 and 85.3 GHz for that of the LSFP-MESFET structure, respectively. The DSFP-MESFET shows a superior maximum stable gain (MSG) exceeding 23.3 dB at 3.1 GHz, which is presenting the potential of the proposed device for high-power operations.

► We propose a 4H–SiC MESFET with double source field plates (DSFP-MESFET).
► The maximum output power density of 24.7 W/mm is achieved.
► We obtain the fT and fmax of 24.5 and 89.1 GHz, respectively.
► A very high maximum stable gain of 23.5 dB at 3.1 GHz has been obtained.
► Realization of the DSFP-MESFET can be completely free of ion implantation.