Sub-threshold analysis and drain current modeling of polysilicon thin-film transistor using Green's function approach

An analytical analysis for a poly-crystalline silicon thin-film transistor is presented. The Green's function approach is adopted to solve the two-dimensional Poisson's equation using Neumann's boundary conditions at the silicon-silicon di-oxide interface. The developed model gives an insight of device behavior due to the effect of traps and also grain-boundary effect. The analysis of threshold voltage depicts short-channel effects and drain-induced barrier lowering. The model is extended to analyze the transfer characteristics and obtain the transconductance of the device. The results obtained show good agreement with the numerical model and with simulated results, thus proving the validity of our model.