SiGe/Si superlattices on implanted buried-oxide structures

In an attempt to reduce the number of threading dislocations propagating through a silicon epitaxial layer grown on an implanted buried-oxide structure, a SiGe/Si superlattice was placed between the initial silicon surface layer and the subsequently grown silicon epitaxial layer. Both the superlattice and the silicon epitaxial layer were formed by molecular-beam epitaxy. Some of the threading dislocations are bent parallel to the superlattice as they propagate through the structure. Some of these are annihilated by interacting with other dislocations while others bend toward the surface again after propagating parallel to the superlattice for some distance. The effect of the superlattice is limited, and many of the dislocations continue propagating through the superlattice toward the surface of the silicon epitaxial layer.