Dynamic R_D Modeling by Exploiting Gate Current Dependency of Virtual Gate Effect

This paper proposes a new method for compact modeling the virtual gate effect by adapting the gate current in the extraction procedure. Drain resistance (R-D) of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) is dynamically varied by time-dependent trapping effects, demanding a high number of measurements for its accurate modeling in scaling-based drain-lag models. We implement insights from physical analysis of the virtual gate effect to make the extraction more efficient and trustworthy. The dynamic R-D extraction is based on a simple dc gate current measurement to emulate its cumbersome nonlinear relation with the drain to source voltage (V-DS). RF large-signal simulations with various cases of R-D modeling are compared, confirming the accuracy of the presented method.