Extremely high gain 0.15 mu m gate-length InAlAs/InGaAs/InP HEMTs

High electron mobility transistors (HEMTs) based on the InAlAs/InGaAs heterojunction grown lattice matched to InP were fabricated with 0.15 μm T-shaped gates. The use of an undoped InGaAs cap layer in the epitaxial structure leads to excellent gate characteristics and very high transistor gain. At 95 GHz, a maximum available gain of 13.6 dB was measured. A maximum frequency of oscillation f max of 455 GHz was obtained by extrapolating from 95 GHz at -6 dB/octave. This is the best reported gain performance for any transistor