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 65), 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.
R.C.Newman, J.H.Tucker, A.R.Brown, S.A.McQuaid: Journal of Applied Physics, 1991, 70[6], 3061-70
Table 65
Diffusivity of O in Si
H-Treatment | T (C) | D (cm2/s) |
furnace | 385 | 6.1 x 10-21 |
furnace | 345 | 3.5 x 10-22 |
furnace | 325 | 1.2 x 10-22 |
furnace | 325 | 8.4 x 10-23 |
plasma | 350 | 2.0 x 10-20 |
plasma | 350 | 1.2 x 10-20 |
plasma | 325 | 3.6 x 10-21 |
plasma | 325 | 2.9 x 10-21 |
plasma | 300 | 3.0 x 10-21 |
plasma | 300 | 2.4 x 10-21 |
plasma | 275 | 3.7 x 10-22 |
plasma | 275 | 2.4 x 10-22 |
plasma | 250 | 1.4 x 10-22 |
plasma | 250 | 1.2 x 10-22 |
plasma | 240 | 6.3 x 10-23 |
plasma | 240 | 4.8 x 10-23 |
plasma | 225 | 1.8 x 10-23 |
plasma | 225 | 1.1 x 10-23 |