Narrow channel effect on the electrical characteristics of AlGaN/GaN HEMT

AlGaN/GaN HEMTs (High electron mobility transistors) with narrow channel were fabricated and the effect of channel scaling on the device were investigated. The devices were fabricated using e-beam lithography to have same channel length of and various channel width from 0.5 to . The sheet resistance of the channel was increased corresponding to the decrease of channel width and the increase was larger at the width of sub-. The threshold voltage of the HEMT with and channel width was -2.85 V. The transistor showed a variation of 50 mV at the width of and the variation 350 mV at . The transconductance of 250 mS/mm was decreased to 150 mS/mm corresponding to the decrease of channel width. Also, the gate leakage current of the HEMT decreased with channel width. But the degree of was reduced at the width of sub-. It was thought that the variation of the electrical characteristics of the HEMT corresponding to the channel width came from the reduced Piezoelectric field of the AlGaN/GaN structure by the strain relief.