Abstract
The mechanical behavior of Czochralski-silicon crystals as influenced by precipitation of oxygen atoms is investigated. The magnitudes of the upper yield stress and of the stress drop after yielding are observed to decrease drastically after annealing at 1050°C and to recover on subsequent annealing at temperatures higher than 1200°C. Changes in the amount of precipitated oxygen atoms due to such annealings are followed. A theoretical analysis of the yield behavior shows that dislocations punched out from precipitates play the most important role in the softening due to precipitation.