The Origin of the Difference in the Mechanical Strengths of Czochralski-Grown Silicon and Float-Zone-Grown Silicon

The mobility of individual dislocations was measured by means of in-situ observations, including the use of X-ray topography, for both Czochralski- and float-zone silicon crystals. No difference in mobilities was found between the two types of crystals. Stress-strain characteristics were also measured for both types of crystals. On the basis of observed facts, it is concluded That the difference in the mechanical strengths of the two types of silicon crystals is associated with the locking effect of dislocations by oxygen atoms.