Growth and annealing effect on the Cu thin film deposited on Si (001) surface

In this work, we used molecular dynamics simulation with the modified embedded atom method to study the deposition and annealing of Cu atoms onto the Si (001) substrate. The effects of the substrate temperature, the deposition rate, and the annealing on the morphology and microstructure of the Cu thin film are investigated. Our results show that at a high deposition rate of 10 at/ps, the Cu atoms grow following an island-like mode, but when the deposition rate decreases to 1 at/ps, the growth mode change significantly and the Cu atoms grow following a layer-by-layer mode. The interface intermixing between Cu atoms and Si substrate is also observed and there are more Cu atoms penetrating into the Si substrate when the substrate temperature and deposition rate increase. On the other hand, based on the radial distribution function, the as-deposited film has an amorphous structure at deposition rates of 10 at/ps and of 5 at/ps. While at a low deposition rate of 1at/ps, the Cu thin film has a crystalline structure. After the annealing process, the film structure is substantially changed from an amorphous state to a crystalline structure.