基于物理并适用于电路仿真的多晶硅薄膜晶体管薄层电荷模型

本文利用薄层电荷理论,建立了一个基于表面势的、物理的多晶硅薄膜晶体管(Polysilicon Thin-Film Transistors,poly-Si TFTs)的电流模型,且该模型适用于电路仿真.推导了 poly-Si TFTs 表面势的近似解法,该求解法非迭代的计算大大地提高了计算效率,且精确度高并得到实验验证.基于物理的迁移率方程考虑了晶界势垒高度,和由于声子散射与表面粗糙散射引起的迁移率退化.基于 Brews 的薄层电荷模型和上述非迭代计算表面势,本电流模型同时考虑了漏致势垒降低(DIBL)效应、kink 效应和沟道长度调制效应.对不同沟长的器件实验数据比较发现,提出的模型在很广的工作电压内与实验数据符合得非常好.同时本模型的所有方程都具有解析形式,电流方程光滑连续,适用于电路仿真器如 SPICE.

A Physics-Based Charge Sheet Model of Polysilicon Thin-Film Transistors for Circuit Simulation

A new physical surface-potential-based current model of polysilicon thin-film transistors (poly-SiTFTs) using charge sheet approach suitable for circuit simulation is presented. An extremely accurate and computationally efficient approximation for the poly-Si TFTs surface potential is derived and verifed. The physics-based mobility equations of the model consider the grain boundaries height and mobility degrada-tion caused by phonon scattering and surface roughness scattering. This model based on Brews's charge sheet model and the above non-iterative computation of surface potential also accounts for DIBL effect,kink effect, and channel-length modulation. Comparison between the model results and measured data shows excellent agreement over wide range of operating voltages and for devices with different channel lengths. All the basic equations in our model have an analytic form for implementation in circuit simula-tors, such as SPICE. And the model exhibits continuity of current expressions which fulfils the require-ment of circuit simulators.