On the origins of structural defects in BF2+-implanted and rapid-thermally-annealed silicon: Conditions for defect-free regrowth

The rapid thermal annealing behavior of BF2+-implanted silicon pre-amorphized with Si+ and Ge+ has been investigated with conventional and high-resolution cross-sectional transmission electron microscopy, and secondary-ion mass spectrometry. Three distinct layers of defects (types I, II and III) are identified. Fine clusters (type III) in the near-surface regions of both Si+ and Ge+ pre-amorphized samples are shown to be related to fluorine. In addition, models for the nucleation of interstitial dislocations loops (type I) and 'hairpin' dislocations (type II) are presented. These models and the experimental results suggest that the densities of type I and type II defects can be reduced by pre-amorphizing with Ge+ instead of Si+. Furthermore, defect-free regrowth is demonstrated for samples which are pre-amorphized with Ge+ and rapid-thermally-annealed at 11500C. (orig.)