The interaction of the 60° shuffle dislocation with the vacancy cluster under applied shear stress in Si crystals was studied here using the molecular dynamics method. The Stillinger-Weber potential and an environment-dependent interatomic potential were used to calculate the interatomic forces. The simulation results showed that, at low shear stresses, the dislocation was pinned by a vacancy cluster. With the stress level increased to a certain critical value, σl, the dislocation could overcome the pinning and get through. It was found that σl reached its maximum at a transition temperature of about 350K. Also revealed by the simulations was a generalized dislocation dissociation that a 60° dislocation, while interacting with a vacancy cluster, could result in 30° and 90° partial dislocations when the applied shear stress reached another critical value σh. The two resultant partial dislocations were separated by an intrinsic stacking fault. Unlike σl, the σh value kept decreasing at temperatures higher than 400K, and remained constant at lower temperatures.

Computer Simulation of the 60° Dislocation Interaction with Vacancy Cluster in Silicon. C.Li, Q.Meng, K.Zhong, C.Wang: Physical Review B, 2008, 77[4], 045211 (5pp)