亚阈值下 MOSFET 氧化层和空间电荷区的二维电势解析模型

摘要

本文用特征函数将因氧化层和空间电荷区衔接条件得到的恒等式作正交展开，把未知量求解转化成一组线性代数方程，得到了二维电势解析表达式，并给出了电势能极值点的计算方法。模型的优点是精度与数值解的精度相同，不含适配参数、运算量小、避免了数值分析时的方程离散化，可直接用于电路模拟程序。文中讨论了亚阈值下NMOSFET的电势分布、阈值电压和界面态电荷的影响。结果表明，该模型与MEDICI结果极其吻合。%A 2-D potential analytical solution in the oxide layer and space charge region is derived .The unknowns are able to be solved by a group of linear equation ,which is orthogonal expanded from the connected condition identity of oxide layer and space charge region .The solution of potential extreme point is also presented .There are many advantages of small calculating amount , without any compromise in accuracy and adapter parameters .Moreover ,this model can be directly used in circuit simulation .The potential distributions and threshold voltage of NMOSFET have been derived in subthreshold .Excellent agreement with MEDICI has been observed .