The diffusion of Sb in Si has been studied as a function of Sn-background concentration, and enhanced Sb diffusion is observed for backgrounds higher than $C_{\mathrm{Sn}}^{\prime }\approx 5\times {10}^{19}{\mathrm{cm}}^{-3\mathrm{}}$. This concentration for the onset of enhanced diffusion is significantly lower than in other reports of high-concentration vacancy-mediated diffusion in Si. These reports, however, have up to now been concerned with donor impurities, whereas Sn is an electrically neutral impurity. Some Sn precipitation occurred, and the influence upon the diffusion is estimated from experiment to be small. A number of proposed models of high-concentration diffusion are discussed on the basis of the data.

• Received 21 September 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.5856