Bias Dependence of Non-Fourier Heat Spreading in GaN HEMTs

In this article, self-heating in gallium nitride (GaN) high-electron-mobility transistors (HEMTs) is studied by combining the technology computer-aided design (TCAD) and phonon Monte Carlo (MC) simulations. The simulation results indicate that the bias-dependent heat generation in the channel can have a remarkable impact on the thermal spreading process and the phonon ballistic effects simultaneously. Based on the two-heat-source model, we propose a two-thermal-conductivity model to predict the device junction temperature with the consideration of bias-dependent phonon transport in the HEMT. The proposed model is easy to be coupled with the finite-element method (FEM)-based thermal analysis without the need for time-consuming multiscale electrothermal simulations.