Characterization of light-activated Cu defects in silicon: Comparison with the recombination activity of metallic precipitates.

The presence of copper contamination is known to severely degrade the minority carrier lifetime of p-type silicon upon exposure to illumination. In this contribution, we have analyzed the recombination activity of light-activated copper defects in deliberately Cu-contaminated p-type silicon by means of a recombination model that quantitatively defines the effect of metallic precipitates on minority carrier lifetime. The excellent agreement between the model and the experimental data indicates that (i) the formation of Cu precipitates is the probable root-cause behind Cu-LID and (ii) in the samples examined in this work, the precipitate radius varies between few to several tens of nm with corresponding densities estimated to be in the range of 108-1010 cm−3. Further evidence of these results was obtained from the analysis of temperature-dependent lifetime data. While applied here to light-activated copper defects, the procedure described in this article can be applied for characterizing lifetime-limiting precipitates originated by other transition metals (e.g., Fe or Ni). [ABSTRACT FROM AUTHOR]