Nonequilibrium point defects and dopant diffusion in carbon-rich silicon

Abstract

We show that B and P exhibit suppressed and As and Sb enhanced diffusion in Si with C atom concentrations of about ${10}^{20} {\mathrm{cm}}^{\ensuremath{-}3}.$ Since B and P diffuse via an interstitial mechanism and Sb and As diffuse via a vacancy mechanism, this indicates a suppressed density of self-interstitials and an enhanced density of vacancies in C-doped Si. Simultaneous measurements of vacancy supersaturation by means of Sb diffusion and of the clustering kinetics of C are used to study the annihilation of excess vacancies at the Si surface. The surface acts as an effective sink for vacancies with a recombination length \ensuremath{\lambda}\ensuremath{\leqslant}70 nm.