Characterization of structural defects in annealed silicon containing oxygen

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Abstract
Transmission electron microscopy has been used to characterize the crystallography of structural defects observed in a Czochralski‐grown silicon crystal after a two‐step annealing treatment. The defect population is complex and consists of precipitates, perfect‐dislocation loops, single and double stacking‐fault loops, microprecipitate colonies on stacking faults, and imperfect/perfect dislocation‐loop pairs. Extensive diffraction‐contrast experiments have been carried out in order to evaluate the nature of these defects. The results indicated that all the observed defects place the surrounding silicon matrix in a comprehensive state (i.e., they are of the so‐called interstitial type). It is clear from the electron‐microscopy observations that perfect‐dislocation loops are generated at the precipitate/matrix interface by prismatic punching. However, the structure and elemental nature of the precipitates is unknown. The role that oxygen may play in the formation of precipitates, perfect‐dislocation loops, and the mechanisms of formation of stacking faults with their associated microprecipitates is discussed. Additional experimental work in the earlier stages of defect formation is required to clarify this picture.