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 and into the bulk, was markedly affected by a surface rate-limiting process. The diffusion data for 1100 to 1250C could be described by:

D (cm2/s) = 2.46 x 100 exp[-3.59(eV)/kT]

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