肖特基势垒碳纳米管场效应管建模方法

Simulation Method for the Schottky Barrier Carbon Nanotube Field Effect Transistor

在肖特基势垒型的碳纳米管场效应管半经典模型中,通常采用WKB(Wentzel-Kramers-Brillouin)近似法求解透射系数,对所有经典转折点复杂的动量-位置关系进行积分,导致运算量巨大。通过研究透射系数的数值计算模型,给出了不同电压下的能带变化情况,分析了z轴方向动量-位置关系式,并进行线性拟合,以拟合值代替原来的积分式,简化了透射系数的求解过程。将基于该算法的模型与半经典模型进行仿真比较,发现两种模型的电压传输特性曲线相似度较高,可见模型精度较好。同时对模型的运行时间进行测试,模型的运算时间约为传统半经典算法的1/20,表明所建模型有效降低了运算量。

Wentzel-Kramers-Brillouin （WKB） approximation method is commonly used in the semi-classical model of Schottky barrier carbon nanotube field effect transistor （SB-CNTFET） for the transmission coefficient. The complex momentum-position relation for each classical turning point is calculated through the integration, which causes huge amount of computation. Energy band diagrams under different biases were given through the research of the numerical model for the transmission coefficient, the momentum-position relation along the transport direction （z） was analyzed and the linear approximation was applied. Then the fitting value was used to substi- tute the original integration, thus the computation of the transmission coefficient was simplified. Through the comparison of the proposed model based on t.he algorithm and the semi-classical model, it is found that the vohage transmission characteristic curves are in high similarity, sug gesting that the proposed model maintains good accuracy. Meanwhile, the simulation time of the proposed model was tested. And the result shows that it reduces the computation to about one twentieth of the traditional method, proving the effective reduction of the built model for the amount of the computation.