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

Abstract

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.