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(fT)is 60 GHz,and the maximum oscillation frequency(fmax)is 104 GHz.The current collapse has improved by 13％at static bias of(VGSQ,VDSQ)=(-8 V,10 V),and gate manufacturing yield has improved by 17％compared with the traditional floating T-shaped gate(FT-gate)device.