In order to establish a suitable model to describe the leakage region of circuit simulators,the leakage generation mechanism of polysilicon thin-film transistors is investigated in terms of current,activation energy and low-frequency noise,etc.Then,based on different leakage mechanisms,some approximations of the generation-recombination model are proposed,and a unified leakage current model suitable for the electric field of 1×106~5×108 V/m is deduced.Moreover,the activation energy models for low and moderate electric fields are derived,and a compact model for low-frequency leakage current noise is put forward.Comparisons between the simulated and the experimental results show that the proposed models are all effective and suitable for circuit simulators.