A simplification method for capacitance models in AlGaN/GaN high electron mobility transistors under large drain voltage using channel analysis

This article analyzes the bias dependence of gate-drain capacitance (C_gd) and gate-source capacitance (C_gs) in the AlGaN/GaN high electron mobility transistors under a high drain-to-source voltage (V_ds) from the perspective of channel shape variation, and further simplifies C_gd and C_gs to be gate-to-source voltage (V_gs) dependent only at high V_ds. This method can significantly reduce the number of parameters to be fitted in C_gd and C_gs and therefore lower the difficulty of model development. The Angelov capacitance models are chosen for verifying the effectiveness of simplification. Good agreement between simulated and measured small-signal S-parameters, large-signal power sweep, and power contours comprehensively proves the accuracy of this simplification method.