Raman scattering studies in phosphorus implanted and laser annealed boron doped Si

Implantation of P in B bulk doped Si (hole concentration = 2.1×1020 cm−3) followed by multiple pulse laser annealing with a XeCl laser has produced the incorporation of P in substitutional sites of the matrix and also charge carrier compensation. We report in this paper light scattering studies of these samples, in which a decrease of the hole-induced softening of the Si-Raman line is observed. This softening depends on the type and concentration of free carriers and thus, in our case, on the degree of compensation. This softening is discussed in terms of the interaction of the continuum of free carrier excitations with the Raman phonon. We also report the observation of the vibrations of 11B-31 P pairs.