Dual-gate crystalline oxide-nanowire field-effect transistors utilizing ion-gel gate dielectric

Abstract

Dual-gate structure field-effect transistors (DG FETs) can provide various advantages such as high output current, enhanced mobility, and tunability of threshold voltage (VTH) by adversely controlling the two channels formed at both top and bottom gate dielectric interfaces. Here, we present high-mobility DG structure FETs using crystalline Ga-doped In2O3 (IGO) nanowires (NWs) as channel and high-k ion-gel as a top gate dielectric layer. To enhance the electrical properties of IGO NW FETs such as field-effect mobility, on/off ratio, VTH, and subthreshold slope, optimization of electrospinning, Ga doping in In2O3 NWs, and thermal annealing was carried out. The optimized IGO NW FETs with a single SiO2 gate dielectric exhibited field-effect mobility of ~6.0 cm2/(V·s), on/off ratio of >107, subthreshold slope of 0.73 V/decade, and VTH of ~0 V. Also, the IGO NW FETs showed excellent operation stabilities under positive-gate-bias and negative-bias-illumination stress conditions. Furthermore, by using a high-k ion-gel film as the second gate dielectric layer, DG IGO NW FETs with field-effect mobility up to ~35.1 cm2/(V·s) were realized which is comparably higher than those of single-gated IGO NW FETs (6.0–6.5 cm2/(V·s)). © 2020 Elsevier B.V.