One-Volt TiO₂ Thin Film Transistors With Low-Temperature Process

Jie Zhang,Yuying Zhang,Chaoying Ni,Yuping Zeng,Peng Cui,Guangyang Lin

doi:10.1109/led.2021.3060973

Abstract

We report one-volt TiO 2 thin film transistors (TFTs) with a low-temperature fabrication process. The TFTs with the 300 °C-annealed TiO 2 channel exhibit a high on/off current ratio ( I ON /I OFF ) of 5.4×10 7 , a low subthreshold swing (SS) of 75 mV/dec and a saturation field effect mobility ( μ sat ) of 2.13 cm 2 ·V -1 ·s -1 under an ultra-low voltage of 1 V. In contrast, the TFTs with the 200 °C-annealed TiO 2 channel show no appreciable currents. Such a distinct conductivity difference is attributed to the crystallinity transformation of stoichiometric TiO 2 , the charge transport of which can be well explained by the multiple-trapping-and-release (MTR) model. The channel/dielectric interfaces of these one-volt TiO 2 TFTs are further investigated by transmission electron microscopy (TEM), multi-frequency ( f) capacitance-voltage (C-V), and conductance-voltage (G-V) measurements. The interface trap density ( D it ) values of ~ 5×10 12 cm -2 ·eV -1 obtained from both C-V and G-V measurements are in good agreement, suggesting a high-quality channel/dielectric interface. These one-volt TiO 2 TFTs show a great potential in emerging applications, such as foldable displays and wearable sensors, where a battery-powered operation is required.

Full Text