Investigation of atomic diffusion behavior of Mo/Au interface

The atomic diffusion behavior of Mo/Au interface was investigated by using molecular dynamics (MD) simulations which combines classical diffusion theory and molecular dynamics simulation, mutual diffusion coefficient and radial distribution function of Mo atoms and Au atoms were obtained. The results indicate that Au atoms can diffuse into Mo layer, while Mo atoms diffuse onto the surface of Au layer extremely difficult. The mutual diffusion coefficients and degree of atomic disorder (Mo and Au atoms) increase with the increase of diffusion temperature. The results were verified by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The Mo 3d characteristic peaks can not be detected on the surface of Mo/Au film at annealing temperature below 673 K, which indicates that Mo atoms can not reach the surfaces of Au layers through the atomic diffusion behavior. The experimental results agree well with the simulation results. However, Mo/Au film structure has been destroyed due to aggregated Au grains at annealing temperature 973 K. Therefore, the experimental results should be taken into account in MD simulations.