A Comprehensive Density-of-States Model for Oxide Semiconductor Thin Film Transistors
Abstract In this paper, a comprehensive Density of States model was proposed to understand the origin of conductivity and the performance of p-type and n-type oxide semiconductor thin film transistors (TFTs). To validate the model, the simulated I-V characteristics are compared with measured results of p-type Cu2O & SnO and n-type SnO2 TFTs. It was found that cation vacancies were responsible for hole conduction in p-type TFTs, while anion vacancies and/or metal interstitial were responsible for electron conduction in n-type TFTs. This was observed by assigning the cation vacancies to acceptor-like Gaussian states and anion vacancies and/or metal interstitial to Donor-like Gaussian states respectively. The characteristic slopes in conduction/valence band-tail states are due to disorders present in the oxide semiconductors. The model is successfully delivering the physical insight and path way to circuit simulation of large scale integration of pixel circuits AMLCD/AMOLED displays.
