Effect of growth temperature on the quality and interfacial thermal conductance of GaN/AlN heterostructure: A molecular dynamics study

As gallium nitride (GaN) based chips advance toward higher frequencies, greater power, and smaller sizes, thermal management has become a critical bottleneck limiting further performance enhancement. During chip fabrication, GaN films are epitaxially grown via techniques such as Metal Organic Chemical Vapor Deposition and Molecular Beam Epitaxy, where the growth temperature is a key parameter. However, the mechanism by which growth temperature affects interface quality and heat transfer characteristics remains unclear. This study employs molecular dynamics simulations to investigate the influence of growth temperature (500–1700 K) on the crystalline quality of grown GaN films and compares the interfacial thermal conductance of GaN/AlN heterostructures under different growth temperatures. The phonon density of states and spectral heat flux are analyzed to elucidate the mechanism by which growth temperature affects interfacial thermal conductance. Results indicate that as the growth temperature increases, the surface roughness of GaN films decreases, crystallinity improves, dislocation density reduces, and overall growth quality is enhanced. The interfacial thermal conductance initially rises and then declines, reaching a maximum value of 535 MW/(m2 K) at a growth temperature of 1000 K. The reason is that the increased number of grain boundaries at lower temperatures impedes heat transport. At high temperatures, although the phonon excitation is enhanced, the newly excited phonons are mainly high-frequency phonons. Most of these phonons fail to match the phonon spectrum of the AlN substrate, resulting in no significant improvement of interfacial thermal conductance. This work deepens the understanding of the role of deposition processes in regulating interfacial heat transfer, providing guidance for optimizing deposition techniques for GaN/AlN heterostructures and thermal design of semiconductor devices.