Epitaxial n-type (111) wafers were implanted with 1.6MeV He+ ions to a dose of 2 x 1016/cm2. Following implantation, the samples were subjected to annealing (800C, 0.5h). Cross-sectional transmission electron microscopy was used to characterize the resultant defects. Even in the case of as-implanted samples, transmission electron microscopic observations revealed the formation of a buried layer which contained a dense array of bubbles. After annealing, a wide band of defects (bubbles, Frank dislocation loops) was observed, as well as rows of prismatic punching-related dislocations which could extend up to several μm from the buried layer. Planar clusters of He bubbles, lying on {001} planes, were also observed and were supposed to be involved in the generation of dislocation loops in the matrix. Their nucleation was considered in terms of a trap-mutation process.

Dislocations Induced by Bubble Formation in High Energy He Implantation in Silicon. E.Oliviero, M.F.Beaufort, J.F.Barbot: Journal of Applied Physics, 2001, 89[10], 5332-8