Modeling of the Ostwald ripening of extrinsic defects and transient enhanced diffusion in silicon

Abstract

We present an atomistic simulation of the Ostwald ripening of extrinsic defects (clusters, {1 1 3}s and dislocation loops) which occurs during annealing of ion implanted silicon. The model describes the capture and emission of Si interstitial atoms to and from extrinsic defects of sizes up to thousands of atoms and includes a loss term due to the flux of interstitials to the recombining surface. Key input parameters of the simulation are the variations of the formation energy and of the capture efficiency with the size of the different defects. This model shows that the kinetics of the well-known dissolution of {1 1 3} defects is only driven by the recombination efficiency at the surface and the distance from the defects to the sample surface. We have subsequently used this model to study defect evolution in low and ultra low energy (ULE) B implanted Si during annealing. Defect dissolution occurs earlier and at smaller sizes in the ULE regime. Consequently, TED is mostly characterized by its “pulse” component which occurs at the very beginning of the anneal.