Microwave operation of sub-micrometer gate surface channel MESFETs in polycystalline diamond

Submicron gate-length metal semiconductor field effect transistors (MESFETs) were fabricated on hydrogen-terminated-large grain polycrystalline diamond. Devices showed high drain-source current (140 ma/mm) and large transconductance values (50 ms/mm), with a cut-off frequency f(r) = 10 GHz and a maximum oscillation frequency, f(max) up to 35 GHz. These values are obtained through the fabrication of devices with geometry and active region dimensions (200-500 nm gate length) compatible with available microelectronic technologies.