Characterization of InAlAs/InGaAs HFETs with High Indium Content in the Channel Grown on GaAs Substrate

InAlAs/InGaAs HFETs having very high indium content (80 and 100%) in the channel have been fabricated on GaAs and electrically characterized. The extrinsic transconductance were 310 mS/mm (560 mS/mm at 77 K), and the saturation current were 700 mA/mm (600 mA/mm at 77 K) for an InAs channel. The value of f_T and f_max for this device were measured to be 80 GHz and 50 GHz, respectively. The In_0.8Ga_0.2As channel material had extrinsic transconductance of 320 mS/mm (470 mS/mm at 77 K), and the saturation current were 520 mA/mm (440 mA/mm at 77K). The value of f_T and f_max for this device were measured to be 80 GHz and 50 GHz, respectively.