Oxygen gettering in low‐energy arsenic or antimony ion implanted Cz‐silicon

Abstract

AbstractLow energy As or Sb ion implantation followed by furnace annealing was used to create ultra shallow junctions. It was found that a significant amount of oxygen was redistributed from the Si bulk to the As implanted layer leading even to an increase of the screening oxide film thickness. Using a marker layer created by implantation of 18O ions, it was confirmed that a large number of interstitial oxygen atoms are transferred from the bulk of the Si wafer to the wafer surface during implanted As activation annealing. Estimation of the O diffusivity in Si during the 950 °C activation anneal, yields a value of about 10–10 cm2 /s which is more than an order of magnitude larger than the literature value which is close to 7 × 10–12 cm2/s. In the case of Sb implantation, the oxygen gettering effect is much reduced. This difference in oxygen behavior can be attributed to the influence of mechanical stress in the near surface highly doped layer. The configuration of the mechanical stress field is different for the cases of As and Sb implantation, with tensile stress dominating for the latter. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)