Transient sputtering of silicon by argon studied by molecular dynamics simulations

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. It is found that, although these potentials both give a reasonably good description of Si, they lead to significant differences in sputter behavior. Briefly said, for MEAM the sputter yield and the fraction of sputtered dimers are higher, frequent sputter bursts occur, the ‘amorphized’ zone is in fact a patchwork of semi-crystalline regions and voids, the average coordination number in amorphized zone is lower, the surface is rougher, and the transient stage lasts longer. All these issues are discussed and possible explanations are proposed.