Effects of crystal structure and surface roughness in sputtering of metals by Ar ions

Abstract

The sputtering of amorphous and crystalline Ni targets by normally incident 0.1–100 keV Ar ions was studied using binary collision simulation. The work was motivated by the fact that for some materials, including nickel, the measured sputtering yields may differ significantly from those calculated for amorphous targets. Taking into account the available experimental data, sputtering by 30 keV Ar ions was studied in detail. Calculations were performed for both flat and rough surfaces using several interatomic potentials. It was assumed that the surface relief has a tooth-like shape observed experimentally. Agreement with the measured sputtering yields was found for the ZBL and Kr-C potentials, while the Zinoviev potential led to a noticeable discrepancy. The main effect of the crystal structure is associated with sputtering due to linear collision sequences (LCS). This is also confirmed by calculations for some other polycrystalline metal targets considered for comparison.