A comparison of molecular dynamic simulations and experimental observations: The sputtering of gold {1 0 0} by 20 keV argon

In order to further illuminate the sputtering process, the bombardment of Au {1 0 0} by 20keV Ar is investigated using molecular dynamics (MD) simulations. The MD results are compared to experimental observations discussed by M.W. Thompson in his recent review of the atomic collision cascade process [Vacuum 66 (2) (2002) 99]. In his review, Thompson explains characteristics of experimental time-of-flight (ToF) and polar distributions using ejection mechanisms. Using mechanisms deduced from the MD results the ToF distributions are divided at 70μs with atoms sputtered by direct recoil at shorter ToF and atoms sputtered by focused collision sequences at longer ToF. Surface lens assisted focusing arises from impacts along crystal symmetry lines (slice impact points) and results in a peak at surface normal in the polar distribution. These conclusions help to clarify the experimental observations made by Thompson and contribute to the overall description of sputtering.