75 nm T-shaped gate for In0.17Al0.83N/GaN HEMTs with minimal short-channel effect

Lattice-matched InAlN/gallium nitride high electron-mobility transistors with a 6 nm-thick InAlN barrier layer were fabricated and characterised. By introducing a very thin InAlN Schottky layer, the short-channel effect could be minimised. The devices with a gate length of 75 nm exhibited output resistance as high as 56.9 Ω mm together with a drain-induced barrier lowering as low as 63 mV/V. The devices also demonstrated excellent high-frequency characteristics such as a unity current gain cutoff frequency (f_T) of 170 GHz and a maximum oscillation frequency (f_max) of 210 GHz.