Ion implantation followed by laser annealing was used to create supersaturated and electrically active concentrations of antimony in Si. Upon subsequent thermal annealing, however, these metastable dopants deactivate towards the equilibrium solubility limit. The formation of inactive antimony structures was studied here with grazing incidence diffused X-ray scattering, and transmission electron microscopy, and the results were correlated to previous high-resolution X-ray diffraction data. It was found that at a concentration of 6.0 x 1020 cm–3, small, incoherent clusters of radius 3–4Å form during annealing at 900C. At a higher concentration of 2.2 x 1021 cm–3, deactivation at 600C occurred through the formation of small, antimony aggregates and antimony precipitates. The size of these precipitates from diffuse X-ray scattering was roughly 15Å in radius for anneal times from 15 to 180 seconds. This value was consistent with the features observed in high-resolution and mass contrast transmission electron microscopy images. The coherent nature of the aggregates and precipitates caused the expansion of the surrounding Si matrix as the deactivation progresses. In addition, the sensitivity of the diffuse X-ray scattering technique permitted the detection of the presence of small clusters of radius ~2Å in unprocessed Czochralski Si wafers. These defects were not observed in floating zone Si wafers, and were tentatively attributed to thermal donors.

Diffuse X-Ray Scattering and Transmission Electron Microscopy Study of Defects in Antimony-Implanted Silicon. Y.Takamura, A.F.Marshall, A.Mehta, J.Arthur, P.B.Griffin, J.D.Plummer, J.R.Patel: Journal of Applied Physics, 2004, 95[8], 3968-76