Extremely High-Speed Lattice-Matched InGaAs/InAlAs High Electron Mobility Transistors with 472 GHz Cutoff Frequency

We report extremely high-speed 30-nm-gate InGaAs/InAlAs high electron mobility transistors (HEMTs) lattice-matched to InP substrates with a record cutoff frequency ft of 472 GHz, the highest value yet reported for any transistor. The ft value exceeds 450 GHz and 400 GHz even for 50-nm-gate and 70-nm-gate devices, respectively. This outstanding performance is attributed to the significantly increased gm achieved by reducing the lateral gate-recess length while maintaining a small gate-to-channel separation, which enhances the average electron velocity under the gate.