Hyperthermal vapor deposition of copper: reflection and resputtering effects

Abstract

Three-dimensional molecular dynamics simulations of hyperthermal copper atom impacts with copper surfaces have been used to investigate the effects of incident atom energy upon atomic reflection and resputtering during physical vapor deposition. No reflection or resputtering has been observed for incident energies below 10 eV. However, as the incident energy was increased to 20 eV and above, the likelihood of both adatom reflection and sputtering of predeposited atoms rapidly increased. The probability of reflection increased with the angle of incidence and was greatest for oblique (glancing) angle impacts. The reflected adatoms were strongly forward scattered and retained a large fraction of their initial incident energies. The resputtering yield was highest for incident angles around 40° to the surface normal. The resputtered atoms were typically ejected with significantly smaller energies than those of the incident atoms, and were preferentially ejected in the forward direction with a maximum probability at an angle of about 45° to the surface normal. These results have been compared with the published experimental data for low energy ion impact. The dependence of the reflection probability, the resputtering yield, as well as the angular and energy distributions of both reflected and resputtered atoms upon the adatom's incident energy and angle have been obtained and fitted to simple relations suitable for incorporation in models of vapor deposition.