O-2-FORMATION AT SI(001)

A 450 eV-3 keV O2+ beam incident at 5° to a carefully flattened Si(001) surface was used to probe the adiabatic potential energy surface for the O2 Si(001) adsorption/reaction system in the limit of low coverage. Over the full incident energy range, O2- an are formed as scattering products. We argue that the O2- product correlates with an O2--like region on the potential energy surface and therefore propose that an O2--like species is an intermediate or precursor in the dissociative adsorption of O2 on Si(001). Classical trajectory calculations indicate that a large amount of collision induced dissociation occurs at all energies. © 1990.