A model for carbon diffusion in silicon that explained carbon diffusion during annealing at 850 and 900C in superlattice carbon structures grown by MBE was implemented using a Monte Carlo atomistic simulator. The C concentrations in the delta layers were 2 x 1020/cm3; exceeding by far the solid solubility. The simple kick-out mechanism which incorporated well-established values of the product of diffusivity and equilibrium concentration of intrinsic point defects, and in-diffusion experiments on carbon in silicon, did not explain observed C diffusion profiles. A more detailed analysis of experiments showed that, in order to fit them, a more unstable Ci was required. The formation of cluster in the simulation was therefore investigated. The formation of carbon/Si self-interstitial clusters promoted the premature break-up of Ci and an increase in the Si self-interstitial concentration in the carbon-rich regions. This led to a better fit to experiment. The low solubility of carbon in silicon at the annealing temperatures explained why the clusters were formed, even under conditions where the self-interstitial concentration was below the equilibrium value.

The Effect of Carbon/Self-Interstitial Clusters on Carbon Diffusion in Silicon Modeled by Kinetic Monte Carlo Simulations. R.Pinacho, M.Jaraíz, H.J.Gossmann, G.H.Gilmer, J.L.Benton, P.Werner: Materials Research Society Symposium – Proceedings, 2000, 610, B7.2.1-6