RF and microwave noise modeling of AlInAs/GaInAs/InP HFETs

Abstract

AlInAs/GaInAs/InP HEMTs were fabricated on a lattice-matched structure, grown by molecular beam epitaxy. An extrinsic transconductance of a g/sub m/=840 mS/mm was obtained at a drain current of 210 mA/mm. RF and microwave noise performance of InP HFETs were investigated in the 2-26 GHz frequency band. Small-signal model parameters were extracted by using the "cold" FET method. AlInAs/GaInAs/InP HEMTs exhibited good RF and noise performance, (f/sub t/=118 GHz, f/sub max/=245 GHz and NFmin=0.4 dB at 2 GHz and NFmin=1.3 dB at 26 GHz). The Pospieszalski noise model in association with a current noise source due to the gate leakage was exploited to account for the measured noise parameters. The good noise characteristics in AlInAs/GaInAs/InP HEMTs can be explained by the low gate resistance and by the suppression of real space transport at the bias of transistor operation due to confinement of electrons in the wide quantum well (300 /spl Aring/) channel. Simulated results gave an error within less than 4%.