Stimulated oxygen impurity gettering under ultra-shallow junction formation in silicon

Ultra-shallow junctions were formed by low-energy As ion implantation followed by furnace annealing. It was found that a significant amount of oxygen is redistributed from the silicon bulk to the As-implanted region. Using a marker layer created by implantation of ¹⁸O isotope, it is confirmed that a large number of interstitial oxygen atoms are transferred from the bulk of Si wafer to the surface during dopant activation annealing, which leads to an increase of the surface oxide thickness. Estimation of the oxygen diffusivity in silicon during the 950 °C anneal, yields a value close to 1 × 10⁻¹⁰ cm² s⁻¹ which is more than an order of magnitude larger than the literature value which is close to 7 × 10⁻¹² cm² s⁻¹. (paper)