A sectioning technique was used to study the diffusion of 71Ge along the [111]-type directions of single crystals doped with P to about 1014/cm3. It was found that, at between 1500 and 1600K, the results could be described by:

D(cm2/s) = 1.535 x 103exp[-4.7(eV)/kT]

This value of the activation energy was in reasonable agreement with a simple theoretical description of impurity diffusion.

The Diffusion of Germanium in Silicon. G.L.McVay, A.R.DuCharme: Journal of Applied Physics, 1973, 44[3], 1409-10