Transient Thermal Analysis of GaN Heterojunction Transistors (HFETs) for High-Power Applications

Transient thermal analysis of GaN heterojunction field-effect transistors (HFETs) was carried out in this letter, with a hybrid nonlinear finite element method (FEM) employed, i.e., combining the element-by-element FEM with the preconditioned conjugated gradient technique. The maximum temperature of the HFETs, strongly depending on the input power density and the duration time of the pulsed heat source, was captured numerically. The effects of temperature-dependent thermal conductivities of the substrates on the maximum temperature were also examined and compared for different substrate materials, such as sapphire, silicon, and SiC