The role of intermediate layers in thermal transport across GaN/SiC interfaces

Interfaces between solid layers in power electronics contribute significantly to the overall thermal resistance, which is a bottleneck for the further advancement of such devices. In many cases, the acoustic mismatch (i.e., phonon spectra mismatch) prevents the efficient heat transfer from one solid to another (e.g., GaN/SiC interface). In this work, we study the effect of intermediate layers on interfacial thermal transport across GaN/SiC interfaces. A series of intermediate layers with different Debye temperatures are studied using molecular dynamics simulations. We find that the overall thermal conductance does not necessarily increase as expected by the acoustic mismatch, but it depends on the overlap of specific phonon spectral peaks between different layer of materials. It is also found that the match of optical phonon spectral peaks also plays important roles in enhancing thermal transport across interfaces. The limitations of our model are also discussed. The results from this work may provide useful information for the design of high power electronics to improve their thermal management solutions.