MBE grown selective recess structures for microwave and millimeter-wave power PHEMTs

Abstract

Two molecular beam epitaxy (MBE) based, single and double selective gate recess structures have been developed to provide superior and high-yield power pseudomorphic high electron mobility transistor (PHEMT) device and monolithic microwave integrated circuit (MMIC) performance at microwave and millimeter wave frequencies. These selective etch PHEMT profiles exhibit a typical breakdown voltage as high as 25 V with a peak transconductance, g m, of over 450 mS/mm and a maximum drain current, I max, of 600 mA/mm. The breakdown voltage improvement from single to double selective gate recessed PHEMTs is achieved mainly by eliminating the surface leakage current with an added heterojunction cap layer at the dielectric passivation interface.