Novel asymmetric gate-recess engineering for sub-millimeter-wave InP-based HEMTs

A self-aligned asymmetric gate-recess structure for ultra-high speed InGaAs/InAlAs high electron mobility transistors (HEMTs) is successfully fabricated. A 50nm-T-shaped-gate HEMT with a longer drain-side recess exhibits a much-improved maximum oscillation frequency (f(max)) of 503 GRz with keeping a similarly high current-gain cutoff frequency (f(t)) of 307 GRz compared to that with a conventional symmetric recess structure. This result indicates reduced electric field between gate and drain with keeping a small source resistance (R-s) in the developed asymmetrically recessed HEMT.