关键词: 多晶硅, 薄膜晶体管, 电流模型, 离散晶界, 表面势, 有效迁移率

Abstract:

The drain current model of the polysilicon thin film transistor ( poly-Si TFT) based on surface potential can not accurately describe the discrete grain boundary distribution,while the threshold-voltage-based model is not capable of continuously representing the drain currents in different operation regions. In order to solve these problems,a direct drain current model of the poly-Si TFT considering the discrete distribution of grain boundary potential in drains is established based on the surface potential. The proposed model describes the drain currents of the poly-Si TFT in different operating regions via an analytic equation.  Simulated results indicate that,when the poly-Si TFT works in the linear region at a certain gate bias,its effective mobility decreases with the increase in drain voltage,and that,with the increase in gate bias or with the decrease in channel length,the effect of drain voltage on the effective mobility weakens.

Key words: polysilion, thin film transistor, current model, discrete grain boundary, surface potential, effective mobility