Suppression of excess oxygen for environmentally stable amorphous In-Si-O thin-film transistors

TL;DR

This paper investigates how excess oxygen affects the stability of amorphous In-Si-O thin-film transistors and demonstrates that adding SiO2 can suppress oxygen out-diffusion, leading to more stable device performance.

Contribution

It introduces a method of using SiO2 doping to suppress excess oxygen in amorphous In-Si-O TFTs, enhancing their environmental stability.

Findings

Excess oxygen causes instability in InOx-based TFTs.

Incorporating SiO2 suppresses oxygen out-diffusion.

Stable TFT operation achieved with sufficient SiO2 doping.

Abstract

We discuss the environmental instability of amorphous indium oxide (InOx)-based thin-film transistors (TFTs) in terms of the excess oxygen in the semiconductor films. A comparison between amorphous InOx doped with low and high concentrations of oxygen binder (SiO2) showed that out-diffusion of oxygen molecules causes drastic changes in the film conductivity and TFT turn-on voltages. Incorporation of sufficient SiO2 could suppress fluctuations in excess oxygen because of the high oxygen bond-dissociation energy and low Gibbs free energy. Consequently, the TFT operation became rather stable. The results would be useful for the design of reliable oxide TFTs with stable electrical properties.