The lattice location of B in Si has been investigated by channelling analyses using nuclear reactions (650keV proton beam, B11(p,α)Be8). The formation at room temperature of a specific, small B complex in presence of an excess of point defects has been inferred. In particular, B implanted in Si or B substitutional dissolved in Si and irradiated with proton beam form a unique B complex with B atoms not randomly located. The angular scans along the ⟨100⟩ and ⟨110⟩ axes are compatible with B–B pairs aligned along the ⟨100⟩ axis. The thermal annealing in the 200–950°C range of the B complexes, analyzed by lattice location and carrier concentration measurements, depends on the residual defect density in the lattice. The B complexes dissolve at low temperature if no excess of Si self-interstitials (Is) exists or they evolve into large B clusters and then dissolve at high temperature if Is supersaturation holds.
14 Nov 2005
Volume: 87 Issue: 20 Pages: 201905
Applied Physics Letters