The electrical properties and distribution of impurities in As+‐ and BF+2‐implanted Si activated using rapid thermal annealing (RTA) are discussed. Sheet mobility and activation of the implanted Si ⟨100⟩ samples (As+: 60 keV, 1×1015cm−2and BF+2: 45 keV, 1×1015cm−2) as functions of annealing temperature are reported for RTA. Secondary ion mass spectroscopy atomic profiles of samples preannealed at 600 °C in furnace, followed by RTA are presented. Full electrical activation of As occurs at 1100 °C and that for B (BF2) occurs at 950 °C. A 600 °C, 1‐h furnace preanneal does not have any noticeable effect on reducing the dopant redistribution during 2‐s, 1170 °C RTA for 1×1015cm−2As+implants and during 2‐s, 1100 °C RTA for 1×1015cm−2BF+2implants. This lack of ‘‘diffusion difference’’ is attributed to the high RTA temperatures at which mechanisms other than the point defects caused early time enhanced diffusion play a dominant role in impurity redistribution.