A novel GaAs Schottky-drain power FET for microwave application

A GaAs Schottky-drain [1] power FET (SDFET) having a 2.4-mm gate periphery and 1.5-µm gate length has been developed, and it realized excellent performance at 10 GHz. This includes an output power in excess of 1 W and 36-percent power-added efficiency (PAE). These devices were fabricated on epitaxial layers grown on 2-µm-thick buffer layers using vapor-phase epitaxy. With the exception of the mesa and recess channels, which were defined by conventional chemical etch, the devices were processed by the plasma dry-etch technique. For the Schottky junctions and source ohmic contacts, we used tantalum with a thick gold overlayer and GeAu, respectively.