Investigating the interface characteristics of high-k ZrO₂/SiO₂ stacked gate insulator grown by plasma-enhanced atomic layer deposition for improving the performance of InSnZnO thin film transistors

Abstract

High-dielectric constant (k) materials have attracted a lot of attention for use as gate insulators (GIs) that enable low-voltage operation of thin film transistors (TFTs). However, high-k GIs also induce severe degradation in TFT characteristics, such as effective mobility (mu(eff)). Therefore, in this study, a stacked GI structure of ZrO₂ and SiO₂ was investigated. The mechanism by which the properties of the high-k GI influence TFT operating characteristics was revealed. Based on this mechanism, an optimized stacked GI structure that exhibited a low subthreshold swing and high mu eff was found and used to achieve low-voltage operation in a TFT device.