HIGH-EFFICIENCY MICROWAVE-POWER ALGAAS INGAAS PHEMTS FABRICATED BY DRY ETCH SINGLE GATE RECESS/

An optimized pseudomorphic high electron mobility transistor (PHEMT) e pitaxial structure processed with a novel single gate recess technique is shown to achieve 850 mW of output power (760 mW . mm(-1) saturated power density) with 50% power added efficiency at X-band when operate d at a CW and nearly class A condition. The multi-finger devices (14 x 80 mu m) retain high extrinsic transconductances (380-420 mS . mm(-1) ), with exceptional breakdown voltage (>18 V). The combination of opti mized epi layer structure design and uniform gate recess using a damag e-free, etch-stop, dry plasma processing step produces consistently an d uniformly high f(T) values (80 GHz at V-DS = 1 V, 35 GHz at V-DS = 7 V) even at low I-DS (100 mA . mm(-1)).