The mechanical strength of dislocated Czochralski-grown crystals was investigated with regard to the precipitation of O at dislocations. It was found that the yield strength increased during the early stages of precipitation of silicon oxide, but decreased markedly during the later stages of precipitation. The enhancement of yield strength was caused by the immobilization of dislocations, due to locking by closely aligned precipitates along dislocations during the early stages of precipitation. The locking effect decreased during the later stages, when precipitates on dislocations coalesced, with the generation of free portions of dislocations with a large separation.

I.Yonenaga, K.Sumino: Journal of Applied Physics, 1996, 80[2], 734-9