a-Si:H TFT亚阈值区SPICE模型的研究

研究了将非晶硅薄膜晶体管（a-Si：H TFT）在电路模拟程序（SPICE）中使用的亚阈值区模型,将亚阈值区分为亚阈值前区和亚阈值后区并建立了模型,对比了不同模型下的模拟结果,发现亚阈值区的TFT特性依赖于材料性质,而且亚阈值前区和亚阈值后区的特性受栅源电压Vcs和漏源电压V DS的影响,呈指数变化。提出的新模型考虑了前界面态、后界面态、局域态、材料及制作工艺等因素,体现了该区域电流对漏源电压Vvs强烈的依赖关系。使用新模型对实验数据的拟合结果优于以往的模型,能够比较精确地模拟亚阈值区的特性,可用来预测a-Si：H TFT的性能．对TFT阵列的模拟设计具有重要价值。

SPICE Model in Sub-threshold Region for a-Si:H TFT

The models for simulation program with integrated circuit emphasis (SPICE) in the sub-threshold I-V region of hydrogenated amorphous silicon thin film transistor (a-SiH TFT) were investigated. The sub-threshold region was divided into a forward sub-threshold region and a reverse sub-threshold region. This paper focuses on the establishment of new model which can describe the I-V characteristics of a-SiH TFT accurately in the forward sub-threshold region and the reverse sub-threshold region. It was found that the I-V characteristics of TFT rely on the material's quality, and models of the forward and reverse sub-threshold region were affected by gate-source voltage (V_(GS)) and drain-source voltage (V_(DS)). The effect follows an exponential function. The new a-SiH TFT models were deve-(loped) to simulate important a-SiH TFT characteristics such as forward sub-threshold current, reverse sub-threshold current, by considering the effect of electron distribution by V_(DS), and the current change due to front interface states, back interface states, localized states, material, process, and so on. Simulation results using these new models showed better agreement with measured data than those presented by other researchers. These models and the modeling process are practical for TFT simulations. This analysis is useful to active matrix LCD designers for evaluating and predicting the performance of a-SiH TFT array.