Short-channel AlGaN/GaN HEMTs with 70 Nm T-gate

The authors have fabricated AlGaN/GaN HEMTs with gate-lengths down to 70 nm to investigate DC- and high frequency characteristics and the breakdown behaviour, respectively. Comparisons with HEMTS fabricated on the same wafer but with a longer gate-length (2 mu m) are presented as well. The 70 nm devices have a transconductance of similar to 155 mS/mm, f(T), is 43 GHz and f(max), similar to 100GHz. Toe breakdown voltage reaches 27 V at I-D 550mA/mm.