Channel-recessed 4H-SiC MESFETs were fabricated and demonstrated excellent small signal characteristics. A saturated current of 250 − 270 mA/mm at Vgs = 0 V and a maximum transconductance of 40 − 45 mS/mm were measured for channel-recessed devices with a gate length of 0.45 m. The three-terminal breakdown voltages (Vds) range from 120 V to 150 V. The Ft and Fmax of the 2 × 200 m devices were measured to be 14.5 GHz and 40 GHz, respectively. The channel recess technique results in a lower saturation current but higher breakdown voltage which makes it possible for the devices to operate at high voltages. Si3N4 passivation suppresses the instability in DC characteristics and improves CW power performance by reducing the surface effects. Less dispersion in the drain current during a power sweep was observed after passivation.