Modeling Bias Dependence of Self-Heating in GaN HEMTs Using Two Heat Sources

This article proposes a new approach for modeling self-heating in gallium nitride (GaN) high-electron-mobility transistors (HEMTs). The proposed approach utilizes two heat sources to model the effects of the relatively uniform heat generation when the device is in the linear regime and the concentrated heat generation in the high-field area after the device pinches off. Compared to traditional single heat source modeling approaches, the proposed approach yields a model that can accurately capture the bias dependence of the heat and temperature distribution in the GaN HEMT channel without resorting to the more resource-intensive electrothermal simulations. It also leads to a simple yet accurate analytical expression for the maximum channel temperature using thermal resistances that have clear geometric dependence.