The locking of dislocations by O was investigated experimentally in Czochralski Si (Cz-Si) with different concentrations of shallow dopants. Specimens containing well-defined arrays of dislocation half-loops were subjected to isothermal annealing at 350 to 550C, and the stress required to bring about dislocation motion at 550C was then measured. This dislocation unlocking stress was found to increase with annealing time due to O diffusion to the dislocation core. By performing a numerical simulation to solve the diffusion equation for O transport to a dislocation, the effective diffusivity of O was deduced, from the dislocation unlocking data, to be given by:

D (cm2/s) = 2.7 x 10-6 exp[-1.4(eV)/kT]

in the highly B-doped Cz-Si. In the temperature range studied, the effective diffusion coefficient in the highly B-doped Cz-Si was found to be approximately 44 times higher than expected in low B doped Cz-Si with an identical oxygen concentration.

J.D.Murphy, P.R.Wilshaw, B.C.Pygall, S.Senkader, R.J.Falster: Journal of Applied Physics, 2006, 100[10], 103531