A molecular dynamics simulation of ultrathin oxide films on silicon: Growth by thermal O atoms and sputtering by 100 eV Ar+ ions

Molecular dynamics was applied to study the growth and sputtering of ultrathin oxide films on (100) Si surfaces. A multibody potential which stabilized the Si/SiO₂ interface was used for this purpose. Oxide growth by exposure to O atoms was found to follow Langmuir-type kinetics with unity initial sticking coefficient of O and saturation coverage of around four monolayers, in agreement with experimental data. Sputtering of an ultrathin oxide film on silicon by 100 eV Ar⁺ ions was simulated to study ion-assisted surface cleaning. Ion irradiation was found to promote restructuring of the surface into oxide islands, as observed experimentally. Island formation was accompanied with an increase in surface roughness. The evolution of the surface state with ion dose was predicted quantitatively