The activity coefficient and B diffusion coefficient in monocrystalline samples were determined at 1064 to 1274K. Surfaces in a quartz capsule were equilibrated with B vapour having a controlled activity. Transferred B then diffused into the Si. The activity coefficient of B was determined from the B concentration at the Si surface; assuming local equilibrium between the B-containing gas and the surface. The B diffusivity coefficient, as determined from the concentration profile, could be described by:

D (m2/s) = 4.9 x 10-7 exp[-3.01(eV)/kT]

Simultaneous Determination of Activity Coefficient and Diffusion Coefficient of Boron in Single Crystalline Silicon. H.Fukuyama, J.Takasago, K.Kawagishi, M.Susa, K.Nagata: Journal of the Electrochemical Society, 2000, 147[5], 1965-9