Molecular dynamic simulation for Cu cluster deposition on Si substrate

Molecular dynamic simulation for Cu cluster deposition on Si substrate was investigated in this work. Tersoff and TB-SMA many-body potentials were used to describe the interaction of Si–Si and Cu–Cu, respectively, and Morse two-body potential was used to describe the Si–Cu atomic interaction. Incident energy, substrate temperature, and cluster size were considered to discuss the critical conditions of epitaxy, mixing, and sputtering modes. Results indicated that interface mixing is easy to occur at the interface and the incident energy is the most important factor to affect the film growth modes. Quasi-epitaxy growth only occurs at very low incident energies, while the sputtering process could start from the incident energy of 40 eV. The increase of substrate temperature and atom number per cluster could slightly help the occurring of film mixing and sputtering. As for the surface roughness, there is a minimum when the incident energy is about 15 eV. The increase of substrate temperature could reduce the surface roughness, while the increase of atom number per cluster could increase the surface roughness. Also, the BDT stresses of the substrate and the film after deposition are discussed.