Spectroscopy of bound multi exciton complexes and deep centers in implanted and annealed silicon

The change of silicon properties relevant to device physics caused by ion implantation and thermal annealing is studied. It is shown that in boron-doped p-Si the increase of P+ ions implantation doses from 1012 to 1014 ions/cm2 lead to a decrease of the broadening of boron bound exciton bands. This behaviour is caused by implantation-induced disordering of the lattice. The subsequent thermal annealing restores the intensity and the halfwidth of the above-mentioned bands and initiates the increase of the bands which correspond to excitons bond on the implanted phosphorus ions. Measurements of phosphorus bound exciton band intensities are applicable to the characterization of the process of phosphorus activation. Analysis of low energy region of luminescence spectra of heat treated samples shows that there is a correlation between the process of implanted phosphorus activation and the one of radiation defects transformation. The influence of germanium doping on the generation of thermal donors by means of spectroscopy of deep centres luminescence has been investigated. It is shown that the introduction of germanium in concentrations of 1019-1020 cm-3 effectively suppresses the generation of thermal donors and deep centres under investigation. (author)