An analytic surface potential based non-charge-sheet poly-Si TFT model including substrate and film thickness effects

An analytic surface potential based non-charge-sheet model for poly-silicon thin film transistors (poly-Si TFTs) is proposed in this paper with consideration of the substrate and film thickness effects. The 1-D Poissonpsilas equation with dopant, mobile, and the trap charge terms is first solved to obtain accurate yet continuous channel potentials physically. An analytic non-charge-sheet drain current model is then derived from Pao-Sahpsilas dual integral as a function of the channel potentials at the source end and drain end. The extensive comparison between the presented model prediction and the 2-D numerical simulation is done, proving accuracy of the developed model. The presented channel potential relation and the physics based TFT drain current model may be useful for device scientists and circuit engineers to further understand TFT device physics and test TFT circuit performance.