Hyperthermal vapor deposition of copper: reflection and resputtering effects

Three-dimensional molecular dynamics simulations of hyperthermal copper ato m impacts with copper surfaces have been used to investigate the effects of incident atom energy upon atomic reflection and resputtering during physic al vapor deposition. No reflection or resputtering has been observed for in cident 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 inc reased with the angle of incidence and was greatest for oblique (glancing) angle impacts. The reflected adatoms were strongly forward scattered and re tained a large fraction of their initial incident energies. The resputterin g yield was highest for incident angles around 40 degrees to the surface no rmal. The resputtered atoms were typically ejected with significantly small er energies than those of the incident atoms, and were preferentially eject ed in the forward direction with a maximum probability at an angle of about 45 degrees to the surface normal. These results have been compared with th e 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 a datom's incident energy and angle have been obtained and fitted to simple r elations suitable for incorporation in models of vapor deposition. (C) 1999 Elsevier Science B.V. All rights reserved.