Photoemission study of monolayer Co on Si 111/ surface

The interaction of monolayer Co with the Si 111. surface is investigated by means of core-level and valence-band photoemission spectroscopy in the range of room temperature to 7008C. Upon increasing the annealing temperature, several formations of silicides are observed. This ultra-thin layer upon annealing at 300–4008C has electronic structure closely related to the metastable CsCl-type CoSi which was discovered by molecular beam epitaxy MBE.grown onto the CoSi2 template to a thickness of ;100 A° . Further annealing up to 5008C leads to the «-CoSi-type electronic structure. Finally, the formation of CaF2-type CoSi2is observed after annealing above 6008C. They lead also to an island formation above 7008C. q1999 Elsevier Science B.V. All rights reserved.