Oxygen precipitation in Czochralski grown silicon heat treated at 550 degrees C

The diffusion of oxygen in silicon at 550 degrees C is studied using small- angle neutron scattering (SANS) and the diffusion coefficient, D, calculate d from Ham's theory is found to be similar to 10 times higher than that exp ected by extrapolation of higher- and lower-temperature data (D = 0.13 exp( -2.53 eV kT(-1)) cm(2) s(-1)). This result confirms previous observations o f enhanced diffusion at intermediate temperatures (400-650 degrees C) altho ugh the magnitude of the enhancement we find is much smaller than that repo rted by some others. At 550 degrees C the precipitates observed initially b y SANS appear to be spherical. For longer annealing times, the scattering b ecomes anisotropic, suggesting that a cuboidal morphology is developing.