Donor Diffusion Dynamics in Silicon

Arsenic, antimony, and bismuth have been diffused into (111) silicon from doped expitaxially deposited source layers in a flowing hydrogen atmosphere. Under intrinsic conditions, the dopant profiles show excellent Fickian behavior. The diffusion coefficients, obtained as a function of temperature, can be described by the following equations: ${D}As=6.55×{}{10}^{{-}2}×{}{exp({-}3.44±{}0.04 eV)}{kT}$ ${cm}²$/sec; ${D}Sb=2.14×{}{10}^{{-}1}{exp({-}3.65±{}0.05 eV)}{kT}$ ${cm}²$/sec; and ${D}Bi=1.08{exp({-}3.85±{}0.06 eV)}{kT}$ ${cm}²$/sec. These data, together with those of phosphorus reported earlier, are shown to be consistent with a point-defect mechanism that involves a closely coupled vacancy-impurity ensemble.