Diffusion Rate of Li in Si at Low Temperatures

Abstract

The method of ion drift in the electric field of an $n\ensuremath{-}p$ junction has been used to measure the diffusion constant of Li in Si between 25\ifmmode^\circ\else\textdegree\fi{}C and 125\ifmmode^\circ\else\textdegree\fi{}C, taking particular care to avoid chemical and electrical interactions which might affect the results. When these data are combined with previous high-temperature data, there is obtained $D=(2.5\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\mathrm{exp}[\ensuremath{-}\frac{(0.655\ifmmode\pm\else\textpm\fi{}0.01)e}{\mathrm{kT}}]$ ${\mathrm{cm}}^{2}$/sec, the data extending over eight decades in $D$. The results are compared with those from ion-pair relaxation experiments, and it is shown that the latter are consistant with the ion-drift results.