The diffusion of antimony in heavily doped and n- and p-type silicon

Abstract

The diffusion of Sb in heavily doped n- and p-type Si has been studied to determine the activation energies and charge states of the point defects responsible for Sb diffusion. It is shown that neutral point defects, probably Vx, dominate under intrinsic doping conditions. For samples doped with high-concentration As or P backgrounds, Sb diffusion is dominated by a double-negatively charge point defect that causes an n2 concentration-dependent Sb diffusivity. Electric-field effects also are important. The measured diffusion coefficients are Dix = 17.5 exp(−4.05 eV/kT), and Di= = 0.01 exp(−3.75 eV/kT). The activation energies are consistent with diffusion via Vx and V= vacancies. Retarded diffusion of Sb in p+-doped samples with uniform B profiles fits an ion pairing model where Sb+B− pairs form to reduce the flux of Sb atoms.