Understanding of multi-way heat extraction using peripheral diamond in AlGaN/GaN HEMT by electrothermal simulations

High power operation of high electron mobility transistors (HEMTs) is limited due to a variety of thermal resistances in the HEMT device causing self-heating effects (SHEs) in the device. To reduce the SHEs, diamond heat spreaders integrated to the device have proven efficient for heat extraction from the device. In this report using electro-thermal TCAD simulations, we demonstrate an understanding of multiway heat extraction utilizing diamond heat spreaders for improving HEMT thermal performance at high DC output power density (~40 W/mm). The impact of each heat extraction pathway is understood while considering the thermal boundary resistance between Diamond/GaN hetero-interface and optimization of the GaN buffer layer thickness. Using these findings, we simulated an AlGaN/GaN HEMT device operating at 40 W/mm DC output power while maintaining device temperature at approximately 470 - 500 K.