Molecular dynamics simulations of plasma-surface chemistry

Molecular dynamics (MD) simulations were conducted of Cl⁺ impact (normal incidence; 10, 25 and 50 eV) onto an initially pure Si surface until approximately steady state Cl coverages had been obtained. A variety of quantities were obtained from these simulations, including steady state Cl coverages, the yields associated with various etching mechanisms and the degree of surface roughness that evolves during surface chlorination. The most direct comparison to experimental measures of etching yield are from vacuum beam experiments utilizing mass- and energy-selected ion beams. In order to compare to these measurements, we took chlorinated Si layers and impacted Ar⁺ upon them at a variety of energies. Quantitative agreement between the simulations and measurements was obtained for ion energies in the range 20-75 eV and qualitative agreement was obtained for 75-300 eV.