Mole fraction effects on Al_xGa_1−xN/AlN/GaN MOSHEMT analog/RF performance: analytical model and simulation assessment

In this work, the authors have investigated and proposed an analytical model for different mole fraction variation for the Al_xGa_1−xN/AlN/GaN MOSHEMT. The mole fraction ‘x’ represents the percentage of Al content in Al_xGa_1−xN. The increase in mole fraction enhances the device performance by increasing band bending and 2-dimensional electron gas (2DEG) charge. The drain current, 2DEG charge, threshold voltage, capacitance, cutoff frequency are analyzed for variation of mole fraction. The model has been validated through comparisons with experimental data and the simulation results from Sentaurus TCAD (Technology Computer-Aided Design). The Al_xGa_1−xN barrier layer with 0.17, 0.2, 0.25 and 0.3 of Al mole fractions are analyzed. The Al_xGa_1−xN/AlN/GaN MOSHEMT produces a high drain current of 772 mA/mm for Al mole fraction of x = 0.3 and transconductance of 288 mS/mm for V_gs of 3 V. The cutoff frequency of 52 GHz achieved with 0.3 mol fraction. The higher the mole fraction of Al gives better the Analog/RF performance which can be used in high power RF/Microwave applications.