Pulsed ruby and CW, Nd-YAG laser annealing of Bi implanted Si single crystals investigated by channeling

Abstract

Abstract The channeling Rutherford back scattering technique (RBS) has been used to investigate pulsed Q-switched ruby laser and CW Nd-YAG laser annealing of ⟨111⟩ Si single crystals implanted with 40-keV Bi to a dose of 1 × 1014/cm2. The pulsed laser annealing completely removed implantation induced lattice damage and left high impurity substitutionality. However, redistribution of Bi atoms occurred in the annealing process; the percentage of impurities, which segregated at the surface reached 30% and 60% for a single pulse and overlapped pulse, respectively. This implies that a surface melting process occurred. The same sample was also annealed by a CW Nd-YAG laser. Backscattering spectra indicated that recrystallization occurred by means of a thermal solid-phase epitaxial regrowth process, which under appropriate conditions optimized almost completely the recovery of the lattice damage, leaving the Bi atoms mainly in substitutional sites (∼90%) without impurity redistribution.