Effect of doping on point defect incorporation during silicon growth

The incorporation of either vacancies or self-interstitials into growing cr ystal is controlled by the V/G ratio (V is the growth rate and G is the nea r-interface temperature gradient). The critical value of V/G for the change -over from interstitial to vacancy incorporation is generally sensitive to the presence of impurities. The most straightforward impurity effect is a s hift in the equilibrium concentrations of defects at the melting point indu ced by a shift in the Fermi level or by lattice strain; the latter effect i s however negligible for conventional dopant concentration. Particularly, t he well-known boron effect on (V/G)(cr) can be attributed entirely to a Fer mi level shift. Some neutral impurities also affect (V/G)(cr). Such phenome na indicate to impurity reactions with intrinsic point defects and particul arly, to transitions between substitutional and interstitial states of impu rity atoms. (C) 2001 Published by Elsevier Science B.V.