Symmetric tilt grain boundary evolution during the growth of copper thin films: Molecular dynamics simulation

Abstract

Molecular dynamic simulations were used to study the evolution of various grain boundaries (GBs) during the growth of the copper (Cu) films, the effects of incident conditions were also considered. Results show that the Cu films mainly exhibit a crystal structure, and the GBs are extended to the epitaxial layer while nearly maintaining its type. With increasing misorientation between nearby tilt grains, the inner defect density increases. The substrate atoms located near the GBs are easily replaced by the deposited atom to form a mixing layer. The increase of the incident energy, and the substrate temperature, or the decrease of the incident angle, all can lead to the increase of the number of the replaced atoms. In short, the GBs are extended to the epitaxial layer, and a vertically incident atom with an incident energy of approximately 5 eV is conducive to form high-quality Cu films.