Level set simulations of dislocation dynamics in biaxially strained, hetero-epitaxial films revealed interesting kinetic and thermodynamic mechanisms for blocking the migration of threading dislocations. Two dislocations on the same or on intersecting slip planes could react to form a threading dislocation segment that did not glide under the influence of the misfit strain. In the co-planar case, a kinetic barrier exists that slows down dislocation migration. For the reaction involving dislocations on intersecting planes, an energetic barrier impedes other advancing dislocations. These barriers create significant and frequent impediment to threading dislocation flow, resulting in pile-ups and high threading dislocation densities.

Dislocation Junctions as Barriers to Threading Dislocation Migration. S.S.Quek, Z.Wu, Y.W.Zhang, Y.Xiang, D.J.Srolovitz: Applied Physics Letters, 2007, 90[1], 011905 (3pp)