It was recalled that when end-of-range defects were located close to, or within, doping profiles they caused diffusion to become anomalous by enhancing the dopant diffusivity and by trapping the dopant. Both effects decreased with time. During annealing, the defects grew in size and their density decreased via the emission and capture of Si interstitial atoms due to Ostwald ripening. It was shown here that, by combining Ostwald ripening theory with transmission electron microscopic observations of the temporal evolution of the dislocation loops during annealing, quantitative information could be deduced which permitted the enhanced diffusivity to be understood. During coarsening, a supersaturation of Si self-interstitial atoms was maintained between the loops, and decreased with time. The enhanced diffusivity was assumed to be related to the evolution of this interstitial supersaturation during annealing, due to the interstitial component of B diffusion. It was shown that the supersaturation decreased sharply during the first second of annealing, and asymptotically approached a value that was just above the equilibrium concentration. It was concluded that this sharp decrease was the cause of the transient enhanced diffusivity of dopants in the vicinity of the loops.

C.Bonafos, D.Alquier, A.Martinez, D.Mathiot, A.Claverie: Nuclear Instruments and Methods in Physics Research B, 1996, 112[1-4], 129-32