Misfit dislocation nucleation and multiplication in fully strained SiGe/Si heterostructures under thermal annealing

An evolution of dislocation structure formed in fully strained Si1−xGex/Si(0 0 1) heterostructures during thermal annealing was studied. Heterostructures with Ge content x=0.15 and 0.30 were grown by MBE on low-temperature Si(400 °C) and SiGe(250 °C) buffer layers. The main attention was devoted to the initial stages of strain relaxation and to the role of intrinsic point defects in misfit dislocation nucleation. A mechanism is proposed for the misfit dislocation nucleation at heterogeneous sources placed within SiGe epitaxial layer.