The design of InAlAs/InxGa1-xAs (x ≥ 0.53) heterostructure insulated-gate FETs with lattice-matched and strained channel designs are investigated. It is shown that DC (gm,K) and microwave (fT, fmax) characteristics were enhanced as the In content was increased to 65% in the InGaAs channel; best performance was μ = 12,890 cm2/V-s, gm = 438 mS/mm, fT = 27 GHz. Orientation effects indicate a Vth shift up to -0.128 V and a very small gm variation. Enhancement- and depletion-mode HIGFET operation was controlled by an additional selective ion implantation in the channel.
