Sputtering from oblique ion incidence using computer simulation technique.

Abstract

A self-contained computer simulation of sputtering from 20 keV incident ions is not possible with present computers. However, a simulation can be done by considering primary and secondary collisions separately. An investigation of 20 keV argon ions incident obliquely on the (100) surface of a face-centered cubic copper crystal was done at angles from 29 to 6l degrees from normal. Results strongly support the concept of transparency, but indicate that focused collision sequences make very limited contributions to sputtering. Depending on the ion beam incidence angle, up to 25 percent of the sputtering may be due to random collision cascades initiated by deep primary collisions. The remainder is caused by surface collision mechanisms. Reflection of incident ions off surface atoms significantly affects argon-copper sputtering when the ions are obliquely incident.