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: $D_{\mathrm{As}}=6.55\mathrm{}\times {10}^{-2\mathrm{}}\times \frac{\exp (-3.44\mathrm{}\pm 0.04 \mathrm{eV})}{\mathrm{kT}}$ ${\mathrm{cm}}^2$/sec; $D_{\mathrm{Sb}}=2.14\mathrm{}\times {10}^{-1\mathrm{}}\frac{\exp (-3.65\mathrm{}\pm 0.05 \mathrm{eV})}{\mathrm{kT}}$ ${\mathrm{cm}}^2$/sec; and $D_{\mathrm{Bi}}=1.08\mathrm{}\frac{\exp (-3.85\mathrm{}\pm 0.06 \mathrm{eV})}{\mathrm{kT}}$ ${\mathrm{cm}}^2$/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.