Si trova su / Altri legami
© 2021 Author(s).Theoretical prediction of sputtering yields of a material subject to ion bombardment requires a detailed knowledge of how atoms in the material interact with other atoms moving with high kinetic energies. In this study, molecular–dynamical (MD) simulations were performed to predict the self–sputtering yields of nickel (Ni) for an incident ion energy ranging from 100 to 4000 eV, modifying existing interatomic potential (or force–field) functions designed for bulk Ni metal in thermal equilibrium. The selection of Ni as a sample material was motivated by an interest in developing damageless etching processes for ferromagnetic materials used in semiconductor devices. The simulations were performed until the system reaches steady state, where surface roughness formed self–consistently owing to the ion bombardment. It has been found that, for high–energy impact, the short–distance atomic repulsion plays a key role in determining the sputtering yields. The Ni self–sputtering yields predicted by the MD simulations of this study were found to be in reasonable agreement with experimental yield data. However, it was also found that two interatomic potential models for Ni that gave essentially the same mechanical properties of metallic Ni gave largely different sputtering yield values. These observations indicate that, for an existing interatomic model to be used effectively to predict sputtering yields of a material by MD simulation, it, in general, requires further modification to represent atomic interactions away from the thermodynamic equilibrium positions.
