New mechanism for dislocation blocking in strained layer epitaxial growth

Dislocation interactions play a critical role in plasticity and heteroepita xial strain relaxation. We use real time transmission electron microscopy o bservations of the interaction between threading and misfit dislocations in SiGe heterostructures to investigate interactions quantitatively. In addit ion to the expected long-range blocking of threading segments, we observe a new short-range mechanism which is significantly more effective. Simulatio ns show that this reactive blocking occurs when two dislocations with the s ame Burgers vector reconnect.