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.