The effect of channel width on the performance of AlGaN/GaN nanowire field effect transistors

AIGaN/GaN nanowire (NW) FETs with a channel width down to -300 nm has been fabricated by "top-down" approach by using electron-beam lithography process. The fabricated AIGaN/GaN NW FETs showed the minimum threshold voltage -3 V, the gate leakage current -10(-10) A/mm, and the maximum transconductance -216 mS/mm, respectively. It has also been demonstrated that the gate controllability of the AIGaN/GaN FETs is improved with decreasing channel width. In the fabricated devices the threshold voltage V(th) for the NW FETs with a width of -300 nm shows a positive shift (deltaV(th) = 2.5 V) with respect to that of the reference FETs. This can be attributed the change in carrier density of the two dimensional electron gas generated at the interface of an AlGaN/GaN.