Ordered structure at Si/Ge interfaces

Abstract

We have determined a 2\ifmmode\times\else\texttimes\fi{}1 ordered Si/Ge interfacial structure on an atomic scale, using grazing incidence x-ray diffraction and high-resolution transmission electron microscopy, and show that the structure differs from previously proposed models that use an atom pump mechanism. The observed structure indicates that atomic replacement during formation of the ordered structure is mainly caused by Ge surface segregation, while atomic-scale strain due to the 2\ifmmode\times\else\texttimes\fi{}1 surface reconstruction determines the atomic configuration of the ordered structure.