Molecular dynamics simulations of ion self-sputtering of Ni and Al surfaces

We present results of molecular dynamics simulations of Ni + impacting Ni(111) and Al + impacting Al (111) and amorphous Al surfaces. Sputter yields and sticking probabilities were calculated as a function of ion fluence, impact angle (0–90°) and energy (25–150 eV). We find that the simulated sputter yields are in reasonable agreement with experiments and a commonly used empirical formula. For Al + impacting at normal incidence, sputter yields were approximately the same for both Al(111) and amorphous Al. The initial penetration depth exhibited a linear dependence with velocity, and was approximately the same for both Al + /Al(111) and Ni + /Ni(111) if the distances were scaled by the lattice constants. The average calculated time between ion impact and atom ejection was less than 25 fs for 100 eV Ni + /Si(111) sputter events.