Molecular dynamics investigation of deposition and annealing behaviors of Cu atoms onto Cu(0 0 1) substrate

The deposition growth and annealing behaviors of Cu atoms onto Cu(0 0 1) are investigated in atomic scale by molecular dynamics (MD) simulation. The results indicate that the film grows approximately in a layer-island mode as the incident energy is from 1 to 5 eV, while surface intermixing can be significantly observed at 10 eV. The surface roughness of the film decreases with increasing the incident energy, and the film after annealing becomes smoother and more ordered. These phenomena may be attributed to the enhanced atomic mobility for higher incident energy and thermal annealing. It also indicates that atomic mixing is more significant with increasing both the incident energy and substrate temperature. In addition, the peak-to-peak distances of radial distribution function (RDF) clearly indicate that the films before and after annealing are still fcc structure except for that at the melting temperature of 1375.6 K. After annealing, the film at the melting temperature returns to fcc structure instead of amorphous. Moreover, the residual stress and Poisson ratio of the film are remarkably affected by the thermal annealing. Furthermore, the density of thin film is obviously affected by the substrate temperature and annealing process. Therefore, one can conclude that high incident energy, substrate temperature and thermal annealing could help to enhance the surface morphology and promote the microstructure of the film.