MESFETs were fabricated on semi-insulating 4H-SiC substrates using e-beam lithography to achieve a gate length of 0.25 mum. The gate-source spacing was 0.5 mum and the gate-drain spacing was varied from 1.25 mum to 3.25 mum. Air-bridges were used to interconnect the source fingers of multi-finger devices and devices up to 3.2 mm periphery have been fabricated. Devices showed an f(MAX) of 38 GHz and an f(T) of 14.5 GHz. A high current gain of 16 dB at 2 GHz was measured while biased at a high operating voltage of 40 volts.