ATOMISTIC MOLECULAR DYNAMICS SIMULATION OF CU THIN-FILM GROWTH UNDER MOLECULAR BEAM EPITAXY CONDITIONS: EFFECTS OF SUBSTRATE TEMPERATURE AND INCIDENT KINETIC ENERGY

Abstract

A molecular dynamics framework was developed to examine the combined influence of substrate temperature and incident kinetic energy on Cu-on-Cu(001) thin-film growth under molecular beam epitaxy (MBE) conditions. The simulations solve Newton's equations of motion using the Mishin embedded-atom method (EAM) potential for Cu-Cu interactions, while incident Cu atoms are introduced normal to the surface with kinetic energies of 0.1, 1, and 5 eV. Substrate temperatures of 300, 500, and 700 K generate a 3 x 3 process matrix. The deposited layer is quantified using vertical extent, RMS vertical spread, coordination number, and average atomic potential energy. The results reveal a non-monotonic morphology response: at 500 and 700 K the 1 eV condition gives the smallest RMS vertical spread, whereas 5 eV increases local coordination and produces a more negative deposited-atom potential energy but also a larger vertical dispersion. The study therefore identifies a competition between impact-assisted atomic rearrangement and morphology roughening. Because the atom arrival rate accessible to MD is much higher than experimental MBE fluxes, the model is interpreted in terms of relative atomistic trends rather than direct experimental growth rates.