Stability Study of ZnO TFT using a Simple and Effective Model

摘要

ZnO TFT is one of the promising candidates as next-generation active addressing devices for FPD. However, its stability has rarely been investigated. Since the microscopic mechanism in the degradation process of ZnO TFT is not clear, a phenomenological model to describe the degradation effect is needed. In this paper, we build a simple yet effective model to investigate the degradation effect of ZnO TFT, where we assume that only charge trapping contributes to the instability. The increasing rate of the ' trapped charge is assumed to be proportional to the difference between the gate voltage and the initial threshold voltage, and inversely proportional to the number of the electrons already trapped. The simulation results agree well with the experimental data for different stressing conditions, proving that our model is effective to investigate the degradation effect in ZnO TFTs. The significations of some key parameters in our model are also discussed.