The as-deposited structure of co-sputtered Cu–Ta alloys, studied by X-ray diffraction and molecular dynamics simulations

Abstract

In this study a direct comparison between lattice spacings predicted by molecular dynamics (MD) simulations and values measured from sputtered Cu–Ta films by X-ray diffraction (XRD) is reported. The study spans the entire composition range between pure Cu and pure Ta and takes into account all the phases documented for the Cu–Ta system in the literature (i.e. α-Cu, α-Ta, β-Ta as well as X-ray amorphous structures). For both the experiments and the MD simulations the results are compared to the literature and discrepancies are critically discussed. A direct comparison between simulation and experiments shows that the MD simulations reproduce the interatomic distances observed in the experiments accurately over most of the composition range, with the exception of alloys with 15–30at.% Ta content where the MD simulations show spontaneous amorphization whereas the experiments suggest that Ta-rich particles are formed in face-centered cubic solid-solution phase.