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 50 nm T-shaped-gate HEMT with a longer drain-side recess exhibits a much-improved maximum oscillation frequency (f/sub max/) of 503 GHz, while retaining a similarly high current-gain cutoff frequency (f/sub t/) of 307 GHz compared to that with a conventional symmetric recess structure. This result indicates reduced electric field between gate and drain while keeping a small source resistance (R/sub s/) in the developed asymmetrically recessed HEMT.