针对非对称双栅结构的非晶硅薄膜晶体管，根据高斯定理建立了表面势与背电势随栅压变化的隐含关联方程组，通过求解一维泊松方程推导了前、背栅压独立偏置条件下统一的沟道电势模型． 该模型所需参数可由实验直接提取，数值拟合量少，在特定条件下可简化为对称双栅模型． 在此基础上，文中利用数学变换及Lambert W 函数提出了表面势与栅压隐含方程的近似求解方法． 数值模拟结果显示，该方法具有良好的数值收敛特性，可直接用于器件仿真软件的初值设定，有效提升了模型自洽解的运算效率．

On the basis of the Gauss's law,two sets of implicit potential equations describing the changes of surface potential and back one with gate voltage are established for asymmetrical dual gate a-Si: TFT thin film transistors.Then,a unified channel potential model with two independent gates is constructed by solving 1-D Poisson equations.This model can be simplified to a symmetric dual gate model under given conditions.In addition,most of relevant parameters can be physically extracted from real experimental data and only few fitting parameters are involved.On this basis,a novel scheme for the approximation of surface potentials is proposed by means of mathematical transformation and by using the Lambert W function.Numerical results show that the proposed scheme is of better convergence and the approximation of those potentials can be directly used to set the initial values of simulation tools,which effectively improves the computation efficiency of self-consistent solutions to the constructed model.