Growth of Al–Cu compound thin film on Si substrate: Molecular dynamics simulation

Abstract

In this study, we have used molecular dynamics simulations to investigate the growth mechanisms of the $\text{AlCu}$ thin film deposited on a Si (001) substrate with different Al:Cu ratios of (1:1, 2:1, 1:2). The interactions between Al, Cu, and Si atoms have been described using the Modified Embedded Atom Method (MEAM). In this study, we investigate how the different Al–Cu compositions and incident energies affect the morphological, structural, and mechanical characteristics. Our results show that the growth occurs via an island growth mode. At 0.1 eV, the deposited film exhibits a surface containing islands under different Al:Cu ratios. However, the islands gradually disappear as the incident energy increases to 0.4 eV. According to the RDF results, the film maintains its amorphous structure despite film composition and incident energy changes. On the other hand, in terms of interdiffusion, the Al atoms penetrate deeper into the substrate than the Cu atoms. Additionally, as the incident energy increased, the rate of penetration intensified. This increase in incident energy also affects the lattice distortion positions within the substrate matrix and internal stress development. Moreover, ${\text{Al}}_2\text{Cu}$ exhibits elevated normal stress values compared to the other studied compositions of Al:Cu.