An improved nonlinear thermal resistance extraction method for AlGaN/GaN HEMTs

Abstract

In this paper, a novel nonlinear thermal resistance extraction method for Gallium Nitride (GaN) high electron-mobility transistors (HEMTs) is presented. Pulsed I–V measurements were performed at different ambient temperatures to extract the relationship between transistor's channel currents and channel temperature under various power dissipations. The temperature-dependent access resistances which play a vital role to the channel currents was also extracted. By using the extracted current-temperature relationship and access resistances, current differences between DC I–V and pulsed I–V were translated into channel temperature differences versus device power dissipations, from which the nonlinear channel thermal resistance was determined. This extraction method was applied to a 400 µm gate widths GaN HEMTs. Finite element analysis (FEA) was also employed for the verification purposes. Results show that this extraction approach can provide accurate power-dependent thermal resistance which is important for GaN HEMTs modeling and reliability assessment.