Shallow BF2 implants in Xe-bombardment-preamorphized Si: The interaction between Xe and F

Si(100) samples, preamorphized to a depth of ∼30nm using 20 keV Xe ions to a nominal fluence of 2×1014cm−2 were implanted with 1 and 3 keV BF2 ions to fluences of 7×1014cm−2. Following annealing over a range of temperatures (from 600 to 1130 °C) and times the implant redistribution was investigated using medium-energy ion scattering (MEIS), secondary ion mass spectrometry (SIMS), and energy filtered transmission electron microscopy (EFTEM). MEIS studies showed that for all annealing conditions leading to solid phase epitaxial regrowth, approximately half of the Xe had accumulated at depths of 7 nm for the 1 keV and at 13 nm for the 3 keV BF2 implant. These depths correspond to the end of range of the B and F within the amorphous Si. SIMS showed that in the preamorphized samples, approximately 10% of the F migrates into the bulk and is trapped at the same depths in a ∼1:1 ratio to Xe. These observations indicate an interaction between the Xe and F implants and a damage structure that becomes a trapping sit...