The interfacial roughness dependence of Cu/diamond thermal boundary conductance: A molecular dynamics study

The enhanced heat transfer at the metal/semiconductor interface is paramount for heat dissipation in electronic devices. In this study, the non-equilibrium molecular dynamics (NEMD) method is employed to elucidate the mechanism of the effect of two-dimensional sinusoidal surface roughness structure on Cu/diamond thermal boundary conductance (TBC). The results indicate that the Cu/diamond TBC increases with the fluctuation height and frequency increase. However, the efficiency of the effect of fluctuation frequency on the TBC varies for different fluctuation heights. The rough interface significantly improves the phonon vibrational coupling between Cu and diamond by phonon density of state (PDOS) analysis. When the interfacial fluctuation height is larger than the phonon wavelength, the increase of phonon reflection point sites further enhances the thermal transport capacity of the Cu/diamond interface, resulting in a significant increase in the growth rate of TBC. The concept of phonon participation ratio is introduced to quantify the effect of interface roughness on phonon localization. Simulations show that phonon localization is almost independent of the interface roughness. This work establishes a foundation for the development of interfacial thermal management techniques.