Evaluation of BBr2+ and B+Â +Â Br+ implants in silicon

The work carried out here examines the suitability of BBr2+ and B+ + Br+ implants into crystalline (1 0 0) silicon for ultra-shallow junctions (USJ) applications. Rutherford backscattering spectroscopy (RBS) shows that an amorphous region is created during implantation of BBr2+, eliminating the need for a separate pre-amorphising implant. This amorphous region re-grows during subsequent rapid thermal annealing and there is evidence that bromine retards the re-growth velocity. Hall Effect measurements after rapid thermal annealing show a difference in electrical activation between the BBr2+ and B+ + Br+ implants with the latter having the lower activation. Anomalous Hall mobility is also observed for the molecular implant at lower annealing temperatures.