Effects of lattice orientation and defect degree on Si/Al solid interfacial structure and thermal resistance

The effect of variation in the Si/Al interface structure on the thermal properties is explored with non-equilibrium molecular dynamics method in present work, and two distinct approaches are employed to manipulate the interface structure. The first is to change the arrangement of the atoms in the Al region by changing the orientation of the axis. The second one is to dig out several layers of atoms near the Al interface, so that the interface appears as a groove-like defect with different depths. Both methods exhibit a direct impact on atomic surface density. The high atomic surface density indicates a more compact atomic arrangement inside the structure, which improves the heat transport. In addition, the internal mechanism of thermal resistance change is probed from the aspects of Grain Boundary (GB) energy, vibrational density of states (VDOS) and the overlap of phonon spectrums parameter. It is found that structures with high atomic surface density correspond to smaller GB energies and larger overlap of phonon spectral parameters. Furthermore, by comparing the two ways of changing the interface structure, it is found that changing the degree of interface defects has a larger effect on the interfacial thermal resistance.