Implantation site of boron in heavily doped silicon: A β-NMR study

Using β-NMR with 12B as nuclear probes the temperature dependence of the lattice-site occupation of boron implanted into heavily doped silicon is studied. In p-type material the unperturbed substitutional fraction of 12B increases from 10% at 300 K to ≅ 40% at 950 K. In n-type material this fraction starting from 20% at 300 K approaches the saturation value of ≅ 80% at 600 K already. This behaviour suggests that the site of implanted boron in silicon is controlled by the Fermi level. (orig.)