X-RAY-DIFFRACTION ANALYSIS OF DAMAGE ACCUMULATION DUE TO THE NUCLEAR-ENERGY LOSS OF 50 KEV AND 1-2.2 MEV B IONS IMPLANTED IN SILICON

Computer simulation of double-crystal X-ray rocking curves was employed to investigate the damage accumulation produced in silicon by implanting increasing doses of boron ions at 50 keV and 1-2.2 MeV energies. Under implant conditions preventing target heating, low-energy-induced damage was found to increase sublinearly with dose. In particular, two trends were observed, characterized by different deviations from linearity. The more marked one is in the range of relatively high doses. This suggests that, besides strain recovery expected by recombination of Frenkel defects of opposite type inside each ion track, which would be consistent with a linear damage growth, a defect recombination mechanism must occur among different tracks, playing a progressively important role at increasing doses. Preliminary results obtained at B energies in the range 1-2.2 MeV seem to indicate that the same mechanisms operate at high implant energy.