OSTWALD RIPENING OF END-OF-RANGE DEFECTS IN SILICON

End-of-range (EOR) defects are interstitial type dislocation loops whi ch nucleate just beneath the crystalline/amorphous (c/a) interface for med by ion implantation in Si, after the preamorphization of the subst rate, and during the ramping-up of the anneal. They originate from the presence of a high supersaturation of ''excess'' Si self-interstitial atoms located just beneath the c/a interface. Upon annealing, the mea n radius of the defects increases while their density decreases throug h the exchange of Si self-interstitial atoms between the loops. The nu mber of interstitials stored in the loops stays constant. For sufficie ntly high thermal budgets, when the nucleation is finished, and when t he local equilibrium between extended and point defects is established , the coarsening of the EOR defects can be modeled through the Ostwald ripening theory applied to the dislocation loops geometry. Indeed, an d as expected from the theory, the square of the mean radius of the lo op population increases with time while the loop density decreases pro portional to 1/t. Furthermore, the theoretical function describing the size distributions perfectly matches the time evolution of the experi mental stack histograms, for different annealing temperatures. During the asymptotic steady-state coarsening regime, the activation energy f or the loop coarsening is 4.4 eV, which is in the range of values give n in the literature for self-diffusion in Si. Nevertheless, an activat ion energy of about 1-2 eV is found during the transient period preced ing the local equilibrium, i.e., in the range of the migration energy of self-interstitials. The limiting phenomenon for the loop growth app ears to be diffusion, since it is the hypothesis that leads to the bes t fit between theory and experiment. An estimate of DiCi has been der ived from the growth laws of the EOR defects. A value of about 1.8x10( 7) cm(-1) s(-1) at 1000 degrees C is obtained and compares well with t he values given in the Literature. (C) 1998 American Institute of Phys ics.