High voltage GaN HEMT compact model: Experimental verification, field plate optimization and charge trapping

Abstract

High voltage GaN HEMTs are leading contenders for power conversion and switching applications [1]. An accurate physics-based compact device model for this emerging technology is essential for device and circuit design. Several GaN HEMT compact models have been discussed but are not physics-based [2]-[3]. Here, a new physics-based compact model for HV-GaN HEMTs, the MIT Virtual Source GaNFET-High Voltage model (MVS-G-HV) is proposed. The model is geometry scalable and captures static and dynamic device behavior through self-consistent current and charge expressions. The access regions, which are important in device linearity [4] and reverse voltage blocking, are modeled as implicit-gated transistors. The model includes the effect of field plates and can be used to maximize the BV2 Gon figure-of-merit. In addition, 'knee-walkout' in these devices is captured in the model through a simple trap-transistor model. The model requires a small number of parameters with straightforward physical meanings and is validated against DC-IV, S-parameter, breakdown and pulsed measurements of fabricated devices. © 2013 IEEE.