Nanoscale electro-thermal interactions in AlGaN/GaN high electron mobility transistors

• DOI: 10.1063/1.5123726
• Publication Date: 2020-01-23T12:33:54Z
• Authors: Bikramjit Chatterjee; Canberk Dundar; Thomas E. Beechem; Eric Heller; Dustin Kendig; Hyungtak Kim; Nazli Donmezer; Sukwon Choi
• Keywords: Electron Mobility; Wide-bandgap semiconductor

Self-heating in AlGaN/GaN high electron mobility transistors (HEMTs) negatively impacts device performance and reliability. Under nominal operating conditions, a hot-spot the channel develops under drain side corner of gate due to concentration volumetric heat generation leading nonequilibrium carrier interactions non-Fourier conduction. These subcontinuum effects obscure identification most salient processes impacting heating. In response, we examine self-heating GaN-on-Si HEMTs via measurements temperature using above-bandgap UV thermoreflectance imaging combination with fully coupled electrothermal modeling. The methods together highlight interplay thermal transport showing that cannot be determined solely by continuum scale transfer principles. conditions equal power dissipation (PDISS = VDS × IDS 250 mW), for example, higher bias (∼23 V) resulted an ∼44% larger rise peak junction compared lower (∼7.5 condition. difference arises primarily reduction generating volume when partially pinched-off (i.e., VDS) conditions. amplifies this as heating now takes place over length scales less than mean free path phonons tasked energy dissipation. Being efficient, restricts away from causing net increase temperature. Taken together, even purely thermally driven mean-time-to-failure is not, therefore, based on alone both dependence influence lifetime.