Behavior of Defects in Heavily Boron Doped Czochralski Silicon

Defect behaviors in heavily boron doped silicon, with boron concentration ranging from 7.1×1017 to 3.1×1019 atoms/cm3, were studied using transmission electron microscopy. The oxygen precipitation and the change of the precipitate morphology from plate to polyhedral were observed to be enhanced with increasing boron concentration. However, in wafers with the highest boron concentration, precipitate density decreased, and aggregations of small polyhedral precipitates on the {110} planes were observed. It was also found that as the boron concentration was increased, the precipitate size reduced and the type of secondary induced defects changed from punching-out dislocations to stacking faults due to the reduction in a crystal lattice strain.