Dislocation formation in homo-epitaxial pyramidal [001] Cu islands under tensile stress was studied using molecular dynamics simulations. It was found that 90° Shockley partial dislocations were dominant in the island strain relaxation. For a low-aspect-ratio island, the dislocations were nucleated from the island surface and propagate downwards to form misfit dislocations. For a high-aspect-ratio island, a pair of the dislocations on the same slip plane were simultaneously nucleated respectively from the two island edges, propagate inwards, and react to form a 90° Shockley misfit partial dislocation. These dislocations could form sequentially and cooperatively.

Molecular Dynamics Study of Dislocation Formation in a [001] Face-Centered-Cubic Epitaxial Island under Tensile Stress. P.Liu, Y.W.Zhang, B.Fox, C.Lu: Applied Physics Letters, 2004, 84[5], 714-6