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 (μeff). 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 μeff was found and used to achieve low-voltage operation in a TFT device.