Abstract
Single crystals of copper were grown with the [111] orientation at a crystal rotation rate varying from O rad・s^<-1> to 4.2 rad・s^<-1> in a strem of purified argon gas by the Czochralski method, and the distribution and density of dislocation in the grown crystals were examined by an etching technique. The following results were obtained. (1) Grown-in dislocations of the order of 10^8/m^2 are dispersedly formed over the cross sections cut along the (111) planes perpendicular to the growth direction of any pulled crystal, while linear arrays of dislocations along <110> direction are also introduced frequently. (2) The distribution of dislocations penetrating the cross sectionsis mainly classified into three types. The type I shows an increases in dislocation density from the crystal center to periphery. The type II has more dislocations at the center of cystal than the type I and shows a nearly homogeneous distribution in the radial direction. The type III shows also a nearly homogeneous radial distribution but the dislocation density is lower than the type II. (3) The average dislocation densities of pulled crystals decreased slightly with an increase of crystal rotation rate.
