基于陷落电荷效应的非晶硅TFT的开态电流模型

对非晶硅薄膜晶体管,提出基于陷落电荷和自由电荷分析的新方法。考虑到带隙中指数分布的深能态和带尾态,给出了基于阈值电压的开启区电流模型。定义阈值电压为栅氧/半导体界面处陷落于深能级陷阱态的电荷与陷落于带尾态的电荷相等时所对应的栅压。电流模型中,引入一陷落电荷参数β,此参数建立了电子的带迁移率与有效迁移率之间的关系。最后,将电流模型同时与Pao-Sah模型和实验数据进行比较和验证,结果表现出很好的一致性。

Above-Threshold Current Model for Amorphous Silicon TFTs Considering Trapped Charge Effect

Based on new analysis of trapped and free charges,an above-threshold current model was presented for amorphous silicon(a-Si:H) thin-film transistors(TFTs),assuming exponential distribution densities of deep and tail trap states(DOS) within energy gap.Threshold voltage was defined as gate voltage when charges trapped by deep trap states were equal to charges trapped by tail trap states on gate oxide/semiconductor interface.A trapped charge parameter β was introduced into the drain current model,which indicated the relationship between electron band mobility and effective mobility.The current model was verified with Pao-Sah model,and compared with experimental data for consistency.Good agreements with Pao-Sah model were obtained.