Effects of a multi-recessed gate in microwave 4H-SiC power MESFETs

Multi-recessed gate 4H-SiC MESFETs with a gate periphery of 5-mm are fabricated and characterized. The multi-recessed region under the gate terminal are applied to improve the gate-drain breakdown voltage and to alleviate the trapping induced instabilities by moving the current path away from the surface of the device. The experimental results demonstrate that microwave output power density, power gain and power-added efficiency (PAE) for a multi-finger 5-mm gate periphery SiC MESFETs with multi-recessed gate structure are about 29%, 1.1 dB and 7% higher than those of the conventional devices fabricated in this work using the same process.