Oxygen Transfer during the Vacuum Annealing of an Ultrathin Sn/Si Epitaxial Layer

The features of the morphology and physical–chemical state of five epitaxially formed monolayers of tin at the interface with a thin silicon buffer layer on a silicon substrate and transformation of the epitaxial structure as a result of in situ thermal annealing from the point of view of the charge state of silicon atoms are studied. X-ray photoelectron spectroscopy using synchrotron radiation and scanning electron microscopy are used. The possibility of oxygen atom transport to the silicon buffer layer during storage of the structures in laboratory conditions is shown. Annealing in ultrahigh vacuum causes a restructuring of the surface of such structures, which is accompanied by oxygen atom redistribution to the exposed surface of the epitaxial silicon buffer with the formation of a thin SiO2 layer and the assembly of tin into clusters on this surface.