A physics based compact model of I-V and C-V characteristics in AlGaN/GaN HEMT devices

In this paper we present a physics-based compact model for drain current I _d and intrinsic gate-drain and gate-source capacitances C _GS and C _GD in AlGaN/GaN high electron mobility transistors. An analytical expression for the 2-DEG charge density n _s, valid in all the regions of device operation is developed and applied to derive current and capacitances. The drain current model includes important physical effects like velocity saturation, channel length modulation, short channel effect, mobility degradation effect, and self-heating. The expression for n _s is used to derive a model for C _GS and C _GD applicable in all the regions of device operation. The parameters introduced in the model have a clear link to the physical effects facilitating easy extraction of parameter values. The model is in excellent agreement with experimental data for both drain current and capacitances over a typical range of applied voltages and device geometries.