A reduction in transient enhanced diffusion, with reduced implantation energy, was investigated. A fixed Si+ dose of 1014/cm2 was implanted into B doping superlattices using energies which ranged from 0.5 to 20keV. Enhanced diffusion of the buried B marker layers was measured after annealing at 810, 950 or 1050C. A linearly decreasing dependence of the diffusivity enhancement, upon decreasing the Si+ ion range, was observed at all temperatures, and could be extrapolated to about unity for 0keV. This was consistent with the expectation that, at zero implantation energy, there would be no excess interstitials resulting from implantation and therefore no transient enhanced diffusion. Monte Carlo modelling and continuum simulations were used to fit the experimental data. The results were consistent with a surface recombination length, for interstitials, of less than 10nm. The data presented demonstrated that, within the range of annealing temperatures of interest for p-n junction formation, transient enhanced diffusion was reduced at smaller ion implantation energies; due to increased interstitial annihilation at the surface.

Reduction of Transient Diffusion from 1–5keV Si+ Ion Implantation due to Surface Annihilation of Interstitials. A.Agarwal, H.J.Gossmann, D.J.Eaglesham, L.Pelaz, D.C.Jacobson, T.E.Haynes, J.E.Erokhin: Applied Physics Letters, 1997, 71[21], 3141-3