Analysis of Heat Diffusion in GaN/3C-SiC/Diamond HEMTs for Design Optimization

This study presents a comprehensive thermal analysis of GaN/3C-SiC/diamond high-electron-mobility transistors (HEMTs), focusing on optimizing heat dissipation through a novel integration of nanosecond transient thermoreflectance (ns-TTR) and Raman thermography. By applying these techniques to fully fabricated devices, we directly measured layer-specific thermal conductivities and boundary resistances using the preexisting gate electrode as the transducer, enabling in situ characterization of thermal properties. Finite element simulations, using ns-TTR-measured parameters and validated by experimental temperature profiles, revealed an optimal thickness-dependent trade-off range in GaN thermal conductivity. These insights provide a framework for designing high-power-density HEMTs with balanced thermal and structural performance, emphasizing the need to optimize GaN thickness and transition layer (TL) properties for efficient heat management.