The formation of vacancy-relatede defects in n-type silicon has been studied immediately after implantation of He, Si, or Ge ions at 85 K using in-situ DLTS. A -center concentrations in He-implanted smaples reach a maximum immediately after implantatio, whereas, with Si or Ge ion implanted samples they continuously increase during subsequent anneals. It is proposed that defect clusters, which emit vacancies during anneals, are generated in the collision cascades of Si or Ge ions. An illumination-induced suppression of A-center formationis seen immediately after implantation of He ions at 85 K. This effect is also observed with Si or Ge ions, but only after annealing. The suppression of vacancy complex formation via photoexcitation is believed to occur due to an enhanced drecombination fo defects during ion implantation, and results in reduced number of vacancies remaining in the defect clusters. In p-type silicon,a reduction in K-center formation and an enhanced migration of defects are concurrently observed in the illuminated sample implanted with Si ions. These observations are consistent with a model where the injection of excess carriers modifies the defect charge state and impacts their diffusion.
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