GaNFET compact model for linking device physics, high voltage circuit design and technology optimization

Abstract

This work is the first demonstration of a physics-based GaN HEMT compact model that is calibrated and verified all the way from individual device-to a HV-buck converter circuit, along with an illustration of use in technology optimization. GaN HEMT based high voltage (HV) switching converters are gaining foothold in the medium voltage (<1000 V) power conversion applications. The superior breakdown voltage, operating frequency, and high temperature performance of GaN HEMTs enable improved conversion efficiency and smaller footprint of the converters [1]. In order to design such high voltage GaN circuits, the device compact model must accurately describe static and dynamic switching behavior to enable designers to gain insight into the impact of the behavioral nuances of the GaN HEMTs on HV circuit performance, such as non-quasi-statics, which is not possible with the available models such as EEHEMT, Curtice, and Angelov models [2]. The model is validated against DC-IV, -CV, and pulsed-IV measurements of fabricated devices and is then verified by comparing measured and simulated signals in a commercial buck converter. Furthermore we demonstrate that our physics-based model can be used as a device design and multi-dimensional optimization tool to estimate device parameters such as field plate (FP) lengths and FP dielectric thicknesses (td) to maximize the switching figure-of-merit (FoM), BV/RonQg.