The relaxation of stress-induced dichroism of the 9000nm O infra-red absorption band was investigated in samples of Czochralski material which had been annealed in H plasma at 225 to 350C. It was found that the in-diffusion of H enhanced the rate of O diffusion, so that dichroism disappeared gradually from the external surfaces. Other measurements indicated that O diffusion jumps were catalyzed by collisions with diffusing H atoms. It was deduced that the H diffusivity was described by:

D (cm2/s) = 1.7 x 102 exp[-1.2(eV)/kT]

It was concluded that H concentrations which were as low as 108/cm3 could significantly enhance O diffusivity.

R.C.Newman, J.H.Tucker, A.R.Brown, S.A.McQuaid: Journal of Applied Physics, 1991, 70[6], 3061-70