Research on self-supporting T-shaped gate structure of GaN-based HEMT devices

A self-supporting T-shaped gate (SST-gate) GaN device and process method using electron beam lithography are proposed. An AlGaN/GaN high-electron-mobility transistor (HEMT) device with a gate length of 100 nm is fabricated by this method. The current gain cutoff frequency (f_T) is 60 GHz, and the maximum oscillation frequency (f_max) is 104 GHz. The current collapse has improved by 13% at static bias of (V_GSQ, V_DSQ) = (–8 V, 10 V), and gate manufacturing yield has improved by 17% compared with the traditional floating T-shaped gate (FT-gate) device.