30-nm-gate InP-based lattice-matched high electron mobility transistors with 350 GHz cutoff frequency

The device characteristics and fabrication of 30-nm-gate InAlAs/InGaAs high electron mobility transistors (HEMTs) lattice-matched to InP substrates ar e reported. The gate length of 30 nm is achieved for a T-shaped gate geomet ry, which is necessary to minimize gate resistance for short-gate HEMTs, by using fullerene-incorporated nanocomposite resist in the electron beam dir ect writing of the bottom of the gate. In addition, the two-step-recess gat e technology is used to minimize the extension of effective gate length. Th e devices provide excellent RF characteristics a record cutoff frequency of 350 GHz is achieved.