亚90nm沟道MOSFET亚阈值状态下二维电势和阈值电压的半解析模型

A 2-D semi-analytical model for electric potential and threshold voltage of the sub-90 nm channel MOSFET in subthreshold state

本文提出一个亚90nm沟道MOSFET在亚阈值状态下的二维电势和阈值电压的半解析模型.文章首先根据短沟道MOSFET在亚阈值状态下的物理模型提出定解问题,然后用特征函数将由氧化层和空间电荷区衔接条件所得到的超越方程组作正交展开,得到关于未知量的线性代数方程组,求出了氧化层和空间电荷区的二维电势、耗尽层厚度和阈值电压的表达式.该模型不需要适配参数,运算量小,避免了方程离散化,计算精度与数值解精度相同.文章给出了沟道长度为90nm以下MOSFET的电势分布、表面势、耗尽层厚度和阈值电压计算结果,计算值与二维数值模拟值高度吻合.

A A 2D semi-analytical model for electric potential and threshold voltage of the sub-90 nm channel MOSFET in subthreshold state is presented in this paper. First, a definite problem is given according to the physical model of the Short Channel MOSFET in sub-threshold state, and then the transcendental equations obtained by using the connected condition of oxide layer and space charge region are expanded by the charac- teristic function. The results are linear algebraic equations about unknown quantities. The 2D electric potential expressions of oxide layer and space charge region, depletion thickness and threshold voltage are obtained by the model. The model is free of adapter parameters, its calculation amount is small, the equation discretion is avoided and the result is as accurate as the numerical solution. The potential distribution, surface potential, depletion thickness and threshold of the MOSFET whose channel length is shorter than 90 nm have been calculated in this paper. It is shown that the calculated results are highly coincident with the 2D numerical simulations.