Competitive gettering of copper in Czochralski silicon by implantation-induced cavities and internal gettering sites

Abstract

The effectiveness of copper gettering by implantation-induced cavities in competition with internal gettering sites in silicon was demonstrated. The cavities were formed in the near surface region by He implantation and annealing while the internal gettering sites were created in the material’s bulk by a ramped hi–lo–hi oxygen precipitation heat treatment. Ion implantation was used to controllably introduce the copper. The quantity of implanted copper was below that corresponding to saturation of solution throughout the wafer at the gettering temperatures of 700 and 800 °C. The cavities were found to be an effective gettering site in the presence of internal gettering sites with only a small amount of copper being gettered at the internal gettering sites. These results have important implications for optimal gettering of metallic impurities from integrated circuit device regions.