The diffusivity of O in Czochralski-type crystals at 400 to 750C (table 80) was deduced from the macroscopic O precipitation behaviour during heat treatment (800C, 4h or 1000C, 16h), using nucleation theory. The O diffusivities at 450 to 650C ranged from 2 x 10-14 to 4 x 10-14cm2/s. These values were considerably higher than accepted normal diffusivities, which were described by:
D (cm2/s) = 1.3 x 10-1exp[-2.53(eV)/kT]
The diffusivity at 450C was found to be roughly proportional to the interstitial O concentration. It was suggested that this dependence of O diffusivity upon interstitial O concentration could be explained in terms of fast-diffusing O molecules.
Diffusivity of Oxygen in Czochralski Silicon at 400-750C. H.Takeno, Y.Hayamizu, K.Miki: Journal of Applied Physics, 1998, 84[6], 3113-7
Table 79
Diffusivity of O in Doped Si
Type | Temperature (C) | D (cm2/s) |
p | 1150 | 2.4 x 10-10 |
p | 950 | 6.4 x 10-12 |
p | 850 | 1.4 x 10-12 |
p | 850 | 7.5 x 10-13 |
p | 750 | 3.3 x 10-14 |
p | 750 | 2.9 x 10-14 |
n | 1150 | 4.3 x 10-10 |
n | 1050 | 6.5 x 10-11 |
n | 950 | 1.4 x 10-11 |
n | 950 | 1.1 x 10-11 |
n | 850 | 1.7 x 10-12 |
n | 750 | 9.6 x 10-14 |
Table 80
Diffusivity of O in Si
Temperature (C) | D (cm2/s) |
400 | 7.1 x 10-15 |
450 | 3.1 x 10-14 |
500 | 2.9 x 10-14 |
550 | 2.0 x 10-14 |
600 | 2.5 x 10-14 |
650 | 3.8 x 10-14 |
700 | 3.1 x 10-14 |
750 | 9.2 x 10-14 |