A width-scalable SPICE compact model for GaN HEMTs including self-heating effect

Abstract

High power operation of AlGaN/GaN HEMTs leads to a high channel temperature and heat dissipation issues which severely degrade the device reliability and power performance. Self-heating effects cannot be ignored when estimating the power performance of HEMTs, and have been an active area of research for a long time [1], [2]. Several methods used for thermal resistance measurements have been proposed in the literature, including techniques to generate comprehensive temperature profiles like infrared thermography, high-resolution Raman thermography [3], [4], etc. These thermography approaches are not always practical as they frequently require specific device samples and prohibitively expensive laboratory equipment. Pulsed measurements enable the determination of thermal resistance across a wide range of ambient temperatures [5], [6] and have been used in this work. The industry standard compact models [7]–[9] account for the self-heating effect using a thermal circuit approach involving parallel RC circuits to represent thermal time constants as shown in Fig 2(c). However, these self-heating models are valid for a narrow range of geometries and are not scalable in the truest sense (as shown in Fig. 1(a)). In this paper we presents a complete SPICE model capable of emulating the geometry-dependent self-heating behavior using a single model card.