TED of boron in the presence of EOR defects: The use of the theory of Ostwald ripening to calculate Si-interstitial supersaturation in the vicinity of extrinsic defects

When end-of-range defects are located close to or within doping profiles they render diffusion ''anomalous'' by both enhancing the dopant diffusivity and trapping it, both phenomena decreasing with time. Upon annealing, these defects grow in size and their density is reduced through the emission and capture of Si-interstitial atoms by a coarsening process called Ostwald ripening. In this paper, we report on how, by coupling the Ostwald ripening theory with TEM observations of the time evolution of the dislocation loops upon annealing, quantitative information allowing the enhanced diffusivity to be understood can be extracted. Indeed, during the coarsening process, a supersaturation, C/C-e, of Si self-interstitial atoms is maintained between the loops and decreases with time. The enhanced diffusivity is assumed to be linked to the evolution of this interstitial supersaturation during annealing through the interstitial component of boron diffusion. We show that C drastically decreases during the first second of the anneal to asymptotically reach a value just above the equilibrium concentration C-e. This rapid decay is precisely at the origin of the transient enhanced diffusivity of dopants in the vicinity of the loops.