It was demonstrated that reactions between extended defects and impurities played a very important role in defect control in semiconductors. Some special types of reaction involving impurity atoms, which did not occur in the matrix of a crystal, could occur in the core region of an extended defect because of peculiarities of its atomic structure. The gettering of impurities by extended defects occurred, as a result of such reactions, at specific temperatures. Impurity gettering by an extended defect caused electrical and optical inhomogeneities in the surrounding region, and such inhomogeneity could be controlled by heat treatment. Impurity gettering also resulted in the immobilization of dislocations. By selecting a suitable heat treatment, the generation of dislocations by structural irregularities could be suppressed.

K.Sumino: Materials Science and Technology, 1995, 11[7], 657-64