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 a H plasma at temperatures of between 225 and 350C. It was found that the in-diffusion of H atoms enhanced the rate of O diffusion (table 78), so that dichroism disappeared gradually from the external surfaces. Other measurements indicated that O diffusion jumps were catalysed by collisions with diffusing H atoms. Increased rates of thermal donor formation were attributed to enhanced long-range O diffusion. It was concluded that H atom concentrations which were as low as 108/cm3 could significantly enhance O diffusivity.

Hydrogen Diffusion and the Catalysis of Enhanced Oxygen Diffusion in Silicon at Temperatures below 500C. R.C.Newman, J.H.Tucker, A.R.Brown, S.A.McQuaid: Journal of Applied Physics, 1991, 70[6], 3061-70

Table 76

Diffusivity of O in Czochralski-Type Si