The effect of dislocation locking by oxygen atoms in silicon has been studide for annealing temperatures between 400 deg C and 850 deg C and annealing times of 0-1300 h. Using an experimental technique based on four-point and three-point bending the unlocking stress of dislocations has been obtained. It has been shown that the unlocking stress increases with increasing annealing temperature, time and oxygen content. At high temperatures, however, after an initial increase the unlocking stress saturates. The saturation time and stress are dependent upon the annealing temperature and oxygen content and decrease with increasing temperature. From the temperature dependence of the saturation stress the binding energy of oxygen atoms to dislocations has been deduced to be about 1.05 eV. The increase of the unlocking stress durign annealing has been used to interpret the oxygen transport to dislocations and to obtain the activation energy of oxygen diffusion in the temperature range 400 deg C-600 deg C.
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