低掺杂多晶硅薄膜晶体管阈值电压的修正模型

对低掺杂多晶硅薄膜晶体管的表面势进行分析,将表面势开始偏离亚阈值区、沟道电流迅速增加时所对应的栅压作为晶体管的阈值电压.考虑到多晶硅薄膜的陷阱态密度为单指数分布,通过对低掺杂多晶硅薄膜晶体管的表面势进行求解,推导出一个多晶硅薄膜晶体管阈值电压解析模型,并采用数值仿真方法对模型进行了验证.结果表明:新模型所得到的阈值电压与采用二次导数法提取的阈值电压相吻合.

Modified Model of Threshold Voltage for Thin-Film Transistors with Low-Doped Polysilicon

For lightly doped polysilicon thin film transistors, the channel current increases quickly when its surface potential deviates from the sub-threshold region. So it can be considered that the corresponding gate voltage is the threshold voltage. Taking the single exponential distribution of trap states density into consideration, explicit simplification and calculation of surface potential is derived, and the analytical threshold voltage model is presented. The results of device numerical simulation indicate that the threshold voltage extracted by the second-derivative method matches perfectly with the threshold voltage model presented in this paper.