Geometric Modeling of Thermal Resistance in GaN HEMTs on Silicon

Abstract

In this article, pulsed measurements ofthermal resistance in GaN-based high-electron mobil-ity transistors (HEMTs) on silicon, with different gategeometries and gate-to-drain extensions, are analyzed andmodeled. Simple expressions for the thermal resistanceof silicon-on-insulator (SOI) MOSFETs, which take intoaccount the gate width and channel length, can be adaptedto model the thermal resistance of these GaN-based HEMTs.Narrow width effects and the increase in the heat flowthrough the gate as the channel length increases werecorrectly reproduced. In addition, numerical simulationswere performed to explain the reduction obtained in ther-mal resistance as the gate-to-drain extension increases.Our approach can also be applied easily to other well-established models using circuit simulators.