An experimental study was made of the interaction between C and interstitials in crystalline material. Superlattices of B-doped material, prepared by means of molecular beam epitaxy, were used to detect the injection of excess Si self-interstitials from near-surface 40keV Si implants (5 x 1013/cm2) during annealing. It was found that interstitial-enhanced diffusion of the B marker layer was entirely suppressed when the C content was increased uniformly from 1018 to 2 x 1019/cm3. This demonstrated that C acted as a trap for interstitials. The incorporation of a buried C layer led to a local reduction in the interstitial concentration without fully obstructing the interstitial flow towards the bulk. The interstitial trapping was thought to involve the formation of mobile C-interstitial complexes which paired with substitutional C and became immobile.

P.A.Stolk, H.J.Gossmann, D.J.Eaglesham, J.M.Poate: Materials Science and Engineering B, 1996, 36[1-3], 275-81