Investigation of Thermal Characteristics of Multilayer Heterostructures for Enhanced <scp>GaN HEMT</scp> Reliability

Abstract

ABSTRACT This study investigates interfacial heat transfer and phonon scattering effects in AlGaN/GaN heterostructures using a modified ballistic diffusive equation (BDE) that incorporates a radiative transfer formulation for quasi‐ballistic heat flux and integrates multiple phonon scattering models (Callaway, Born–Von Karman, Holland). Finite element simulations reveal that Umklapp scattering markedly reduces the effective thermal conductivity as both temperature increases and layer thickness decreases. A comparative analysis between Al 0.17 Ga 0.83 N and Al 0.32 Ga 0.68 N layers highlights distinct thermal conductivity trends, primarily due to enhanced boundary scattering in the higher aluminum‐content layer. The temperature distribution exhibits a pronounced peak within the GaN channel, followed by a rapid decline across the Al 0.32 Ga 0.68 N barrier, emphasizing the localized nature of heat generation. Overall, the results demonstrate that phonon scattering mechanisms and material composition have a decisive role in controlling phonon transport at nanoscale interfaces, providing essential insights to improve thermal reliability of GaN HEMT devices.