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

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.