Electro-Thermal Simulation of GaN HEMT Based on a Scaling-Factor-Enhanced Time-Domain Spectral Element Solver

This article proposes a high-precision simulation method for transient electro-thermal coupling to characterize the self-heating effect in gallium nitride high electron mobility transistors (GaN HEMTs). The method is based on governing coupled drift-diffusion and heat conduction equations. A time scaling factor is introduced for the first time to accelerate the simulation process of electro-thermal coupling in GaN HEMTs. The technique addresses the cross-scale issue associated with the electrical and thermal response times encountered during the solution of the nonlinear coupling equations for GaN HEMTs. An accurate spectral element time-domain (SETD) method was utilized for the numerical realization of the nonlinear equations. The selection rules for the time scaling factor are discussed and exemplified through numerical simulations. By compared with commercial software, the advantages of the proposed method are demonstrated in terms of efficiency, accuracy, and random access memory (RAM) requirements. Based on its ability to accurately take into account electro-thermal coupling, this technique represents a powerful simulation tool for the design of high-performance devices and heat management.