A Compact Physical AlGaN/GaN HFET Model

We introduce a physics-based compact model for AlGaN/GaN heterojunction field-effect transistors (HFETs) that is suitable for both RF microwave and switched-mode power supply (SMPS) applications, so that RF techniques can help determine HFET performance in SMPS applications. Such simulations can predict the on-resistance, slew rate, and breakdown voltage from the physical design of the transistor. Starting from an expression for the drain-source conduction current, charge distribution and displacement current are determined. The new model was implemented in Verilog-A and implemented in AWRDE, the design environment from Applied Wave Research. The HFET model was validated by comparison with Silvaco simulations and with data from an AlGaN/GaN HFET S-band amplifier. The new model accurately predicts device performance for dc, small-signal, and large-signal operations.