Performance and microstructure analysis of vacuum annealed ZnO thin-film transistors

This paper examines the performance of intrinsic ZnO thin-film transistors (TFTs) with and without vacuum annealing. The fabricated ZnO-TFTs, which are annealed in vacuum ambient at low temperature with proper time, have shown satisfying performance, comparing with the as-deposited devices. There are no significant changes observed during the analysis of the structural properties and surface morphologies of ZnO films, including X-ray diffraction and atomic force microscopy. However, we find the increase of oxygen loss in ZnO thin films with increasing the annealing temperature, which is measured by X-ray photoelectron spectroscopy. The data obtained by scanning auger microprobe further verify our proposition. The enhancement of ZnO-TFTs´ characteristics is strongly correlated with the oxygen vacancy defect in ZnO thin film.