Gettering sinks for metallic impurities formed by carbon-cluster ion implantation Zip Ties in epitaxial silicon wafers have been investigated using technology computer-aided design and atom probe tomography (APT).We found that the defects formed by carbon-cluster ion implantation consist of carbon and interstitial silicon clusters (carbon-interstitial clusters).Vacancy-type clusters are not dominant gettering sinks for metallic impurities in the carbon-cluster ion implanted region.APT data indicated that the distribution of oxygen atoms in the defects differs between Czochralski-grown silicon and epitaxial silicon wafers.
The high gettering efficiency observed in carbon-cluster ion Outdoor Round End Table implanted epitaxial silicon wafers in comparison with Czochralski-grown silicon wafers is due to the distribution of oxygen atoms in the defects.Defects not containing O atoms provide strong gettering sinks for metallic impurities.These defects are formed by only carbon-interstitial clusters.Oxygen atoms inside the defects modify the amount of carbon-interstitial cluster formation on the defects.
It is suggested that the gettering efficiency for metallic impurities in carbon-cluster ion implanted epitaxial silicon wafer is determined by the amount of carbon-interstitial clusters.