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We have classified the surface defects present in two kinds of wafers processed by high-dose separation by implanted oxygen (HD-SIMOX), for which the starting substrates were grown by the Czochralski (CZ) and epitaxial (EPI) methods, respectively. Our classification included several kinds of categories, based on our investigations of the densities and distributions of these defects. In addition, we varied the shapes of the defects by sacrificing the oxide layers, and investigated their cross-sectional structure. The two main classes of surface defects are pit-type defects and undulation-type defects. Our view is that the former are attributable to grown-in defects such as crystal-originated particles (COPs), the latter to the behavior of these particles during the implantation and SIMOX anneal stages. We also investigated the influence of surface defects on the integrity of the oxide layer and the quality of the buried-oxide (BOX) material. We found that some undulation-type defects that lose the silicon-on-insulator (SOI) layer during the thinning process can degrade the oxide film integrity, while those defects that lose both the BOX layer and the SOI layer during the thinning process can lead to both degradation of the oxide film integrity and BOX leakage. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(7): 64–72, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.1125 [ABSTRACT FROM AUTHOR]

The gettering mechanism of Cu and Co in various wafers has been quantitatively studied by the measurement of Cu and Co distribution using radioactive isotope tracer method. We found quantitative gettering of Cu and Co in P/P+ epitaxial wafer with polyback seal (PBS) and bulk micro defect (BMD), respectively. On the other hand, P+ substrate was not an effective gettering site for Co because of no Coulomb interaction between Co0 and high boron in the substrate of epitaxial wafer. In the case of Cu, the high boron concentration in the substrate of P/P+ epitaxial wafer without PBS has a strong gettering effect due to Coulomb interaction. [Copyright &y& Elsevier]