Molecular dynamics simulation of silicon sputtering: sensitivity to the choice of potential

Abstract

Molecular dynamics simulations of Si(0 0 1) targets subject to uninterrupted Ar bombardment of various energies and angles of incidence were performed, in order to study the atomic processes that take place during the transient and steady state sputtering regimes. Silicon interactions were described with the Modified Embedded Atom Method potential and the Stillinger–Weber potential. Detailed information is extracted and briefly discussed. It is found that these potentials lead to significant differences in sputter behavior. By testing these potentials (and two others) against newly calculated DFT data for Si energies in a wide variety of atomic environments, we demonstrate that they all have severe shortcomings. Therefore, the Modified Embedded Atom Method potential was re-fitted to the DFT data, leading to a new parametrization and a greatly improved fit. However, a spurious ‘amorphous phase’ energy minimum was detected during molecular dynamics simulations at room temperature. Roads to dealing with this problem are discussed.