A Closed-Form Model for N-Polar Gallium Nitride Heterostructures

The closed form model to calculate the charge density and surface potential in an N-polar GaN/AlGaN heterostructure is presented. The proposed model is developed from the solution of Schrodinger’s equation for a finite triangular potential well. The results from our model are validated with numerical data for a wide range of bias conditions, channel layer thickness and spacer layer mole fraction. Finally, the gate capacitance of the heterostructure is evaluated using automatic differentiation and validated against experimental data. This model will be useful in the development of closed-form current-voltage models for circuit level analysis involving N-polar MIS-HEMTs.

本文提出了一种用于计算N极性GaN/AlGaN异质结构中电荷密度与表面电势的闭式模型。所提模型基于有限三角势阱的薛定谔方程（Schrödinger’s equation）求解构建而成。针对宽范围偏置条件、沟道层厚度与间隔层摩尔分数，将模型结果与对应数值仿真数据进行了验证。最后，采用自动微分（automatic differentiation）方法对该异质结构的栅电容进行了求解，并通过实验数据完成验证。本模型可用于开发面向N极性金属-绝缘体-半导体高电子迁移率晶体管（MIS-HEMTs）的电路级分析闭式电流-电压模型，具备重要应用价值。