The dopant was diffused into (111) single crystals having dislocation densities of less than 500/cm2, under intrinsic vacuum sealed tube conditions. It was found that the low concentration migration of the dopant from the vapor phase into the bulk was markedly affected by a surface rate limiting process. The diffusion data for between 1100 and 1250C could be described by:

D(cm2/s) = 2.033 x 101exp[-3.87(eV)/kT]

R.N.Ghoshtagore: Solid State Electronics, 1972, 15, 1113-20