The effect of substitutional C upon interstitial-enhanced B diffusion was investigated. The substitutional C was incorporated into B-doped superlattices by using molecular beam epitaxial growth under acetylene gas. Excess Si self-interstitials were generated by near-surface Si implantation (5 x 1018/cm2, 40keV) and diffusion at 790C. It was found that the interstitial-enhanced diffusion of the B marker layers was entirely suppressed by a C concentration of 2 x 1019/cm3. This demonstrated that substitutional C acted as a trap for interstitials in crystalline Si. The uniform incorporation of 5 x 1018/cm2 of C significantly reduced the transient enhanced diffusion of a typical B junction implant without perturbing its electrical activity.

P.A.Stolk, D.J.Eaglesham, H.J.Gossmann, J.M.Poate: Applied Physics Letters, 1995, 66[11], 1370-2