Accurate determinations of the intrinsic diffusivities of B, P and As in Si were reported. It was shown that the differences in the B, P and As diffusivities reported previously arose from SiO2 films on the Si sample surfaces. Impurity diffusion near to a Si surface without SiO2 was affected by the oxidation of Si even in a nominally inert atmosphere, which had an unavoidable residual O background due to the open furnace. On the other hand, a surface SiO2 film of ~20nm in thickness prepared before diffusion annealing was sufficient to block further oxidation of Si. That is, truly intrinsic diffusivities for the impurities were obtained from samples having surface oxide layers.

Accurate Determination of the Intrinsic Diffusivities of Boron, Phosphorus, and Arsenic in Silicon: The Influence of SiO2 Films. M.Naganawa, Y.Kawamura, Y.Shimizu, M.Uematsu, K.M.Itoh, H.Ito, M.Nakamura, H.Ishikawa, Y.Ohji: Japanese Journal of Applied Physics, 2008, 47, 6205-7