Control of transconductance in high performance AlGaN/GaN FinFETs

AlGaN/GaN-based fin-shaped field-effect transistors (FinFETs) with very steep sidewall and various fin-widths (Wfin) have been fabricated by utilizing electron-beam lithography and additional anisotropic sidewall wet etch in TMAH solution. The device with Wfin of 150 nm exhibits normally-on performance with threshold voltage of -2.5 V, suppression of current collapse phenomenon, low gate leakage current (10^-11 A), low subthreshold swing (SS) of 68 mV/decade, and high linearity characteristic with extremely broad transconductance (gm). On the other hand, devices with Wfin = 50 and 70 nm exhibit normally-off performance with positive threshold voltage of 3.0 and 1.5 V, respectively, and less broad gm characteristics.