The growth of isotopically enriched epitaxial Si and SiGe layers enables the preparation of material heterostructures, highly appropriate for simultaneous self- and dopant-diffusion studies. The advance in solid state diffusion was demonstrated by dopant diffusion in isotopically controlled Si multi-layer structures. Experiments on B, As and P diffusion were presented indicating that dopant diffusion strongly affects self-diffusion. The demand to describe both the self- and dopant-profiles sets strong constraints as to the underlying mechanisms of atomic transport and the properties of the point defects involved. The relative contributions to dopant diffusion and the type and charge state of the native point defects involved were determined. The energy level scheme deduced for the native defects showed a reverse level ordering for the donor levels of the self-interstitials, that is, the doubly positively charged self-interstitial mediated the extrinsic diffusion of B and the self-diffusion via self-interstitials under p-type doping. Self-consistent modelling of P and Si profiles requires that a mobile positively charged P defect exists. This defect and the supersaturation of self-interstitials were responsible for the tail observed after P diffusion.

Advanced Dopant and Self-Diffusion Studies in Silicon. H.Bracht: Nuclear Instruments and Methods in Physics Research B, 2006, 253[1-2], 105-12