The Effect of Density-of-State on the Temperature and Gate Bias-Induced Instability of InGaZnO Thin Film Transistors

Abstract

The impact of a gate insulator (GI) material on the device instability of InGaZnO (IGZO) thin film transistors (TFTs) was investigated. The IGZO TFTs with GI showed consistently better stability against the applied temperature stress and positive/negative gate bias stress than their counterparts with GI. This superior stability of the -gated device was attributed to the reduced total density of states (DOS) including the interfacial and semiconductor bulk trap densities. Based on the Meyer–Neldel rule, the total DOS energy distribution for both devices was extracted and compared, which can explain the experimental observation.