The diffusivity of B in amorphous silica films was studied at 1173 to 1373K. The films had been prepared by the thermal oxidation of Si substrates. The B was introduced from B vapor at pressures of 5.5 x 10-18 to 7.2 x 10-13Pa. The coefficients were deduced from the B concentration profiles, as measured by using secondary ion mass spectrometry. It was found that the results could be described by:

D (cm2/s) = 1.88 x 10-7exp[-48.8(kcal/mol)/RT]

The diffusivity did not depend upon the B concentration at the film surface. It was suggested that the B diffused through Si sites in the silica network.

K.Hawagishi, M.Susa, T.Maruyama, K.Nagata: Journal of the Electrochemical Society, 1997, 144[9], 3270-5

The best linear fit to the solute diffusion data ([444] to [446]) yields:

B: Ln[Do] = 0.11E – 21.2 (R2 = 0.73)