Involvement of the topmost Ge layer in the Ge surface segregation during Si/Ge heterostructure formation

Abstract

Surface segregation of Ge atoms during Si/Ge heterostructure formation by molecular beam epitaxy has been investigated by x-ray photoemission spectroscopy varying the Ge layer thickness. It has been found that only the Ge atoms of the topmost layer are involved in the surface segregation, leaving the rest of the Ge atoms intact. This result supports the basic idea of the two-state-exchange model.