The diffusivity of B in amorphous silica films was studied at temperatures ranging from 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 between 5.5 x 10-18 and 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 (m2/s) = 1.88 x 10-12exp[-205(kJ/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