Level set simulation of dislocation dynamics in thin films

We develop a level set method-based, three-dimensional dislocation dynamics simulation method to describe the motion of dislocations in a heteroepitaxial thin film. The simulations accurately describe the elastic interactions of the dislocations, stress fields throughout the film and substrate, dislocation annihilation, and dislocation reactions. As an example application, we consider the expansion of dislocation half-loops in a Si_1-ηGe_η thin film on a Si substrate. The expansion of the loop(s) creates interfacial misfit dislocations connected to propagating threading segments. The simulations show cross-slip of screw segments from one (1 1 1) glide plane to another, topological changes, and thermodynamically favorable dislocation reactions.