Fin-Gated Nanochannel Array Gate-Recessed AlGaN/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistors

In this article, fin-gated nanochannel array gate-recessed AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs) were fabricated, in which the gate oxide layer was directly grown using the photoelectrochemical (PEC) oxidation method, the gate-recessed structure was formed using the PEC etching method, and the nanochannel array was patterned using the electron-beam lithography system. The improved gate controllability was obtained in devices with a narrower channel width due to the lateral field effect in comparison with those of the conventional planar AlGaN/GaN MOSHEMTs. A threshold voltage of -0.30, -0.35, and -2.3 V, and a subthreshold swing of 95, 109, and 372 mV/dec, were respectively obtained for the AlGaN/GaN MOSHEMTs with a channel width of 80 and 100 nm, and with a planar channel. Furthermore, the associated extrinsic transconductance of 269, 253, and 93 mS/mm was obtained to verify the improved performance of AlGaN/GaN MOSHEMTs using a narrower channel array. Besides, the low-noise and high-frequency performances were also enhanced using a narrower channel width in the fin-gated nanochannel array gate-recessed AlGaN/GaN MOSHEMTs.