HIGH-PERFORMANCE IN0.3GA0.7AS IN0.29AL0.71AS/GAAS METAMORPHIC HIGH-ELECTRON-MOBILITY TRANSISTOR/

A new high-electron-mobility transistor (HEMT) using InAlAs/InGaAs gro wn by molecular beam epitaxy on GaAs has been successfully realized. T his device, having an In content close to 30%, presents several advant ages over conventional pseudomorphic HEMTs on GaAs as well as over lat tice matched HEMTs on InP. High electron mobility with high two-dimens ional electron gas density (25000 cm(2)/V.s with 3 x 10(12) cm(-2) at 77 K) as well as high Schottky barrier quality (V-b=0.68 V with eta=1. 1) has been obtained for this material system. A 0.4-mu m-gate-length device showed an intrinsic transconductance as high as 700 mS/mm with f(t)=45 GHz and f(max)=115 GKz while a minimum noise figure of NFmin=1 .1 dB at 18 GHz has been obtained with a 0.2 mu m device. This perform ance is, to the authors' knowledge, the first reported for submicromet er-gate metamorphic InAlAs/InGaAs/ GaAs HEMTs.