Mechanism of dislocation generation in heterostructures based on SiGe alloys

The structure of SiGe-based heterostructures grown on Si(001) and at Ge(111) substrates have been studied by the methods of molecular beam epitaxy, with the use of various sources, and hydrid vapar-phase epitaxy. The data on the kinetics of development of a dislocation structure in the process of epitaxial growth are presented for the first time. The dependences of the threading dislocation density in the layers on the alloy composition are analyzed theoretically for three types of heterostructures. It is established that a dislocation structure in such heterostructures is formed as a result of the combined action of bending, wafer-edge nucleation, loop mechanisms of misfit dislocation generation, and the multiplication of misfit dislocation the networks at the heteroboundary