Oblique stacking of three-dimensional dome islands in Ge/Si multilayers

Abstract

The organization of Ge “dome” islands in Ge/Si multilayers has been investigated by cross-sectional transmission electron microscopy. Ge domes are found to spontaneously arrange in oblique stacks, replicating at a well-defined angle from one bilayer to the next. The formation of oblique island stacks is governed by a complex interplay of surface strain, generated by the already buried islands, and surface curvature, caused by the inherent tendency of large domes to carve out material from the surrounding planar substrate.