ION IMPLANTATION OF SILICON: I. ATOM LOCATION AND LATTICE DISORDER BY MEANS OF 1.0-MeV HELIUM ION SCATTERING

The implantation behavior of Sb in silicon has been investigated by studying the orientation dependence of the backscattering yield of a 1.0-MeV helium beam. This orientation dependence ("channeling") provides quantitative information on the location of implanted atoms in the lattice and also on the amount of lattice disorder accompanying the implantation. The general principles of the channeling technique and the advantages of using a beam of He+ rather than H+ are discussed. Results for 25 °C and 450 °C implantations are presented and compared. The hot implant introduces very little lattice disorder, and a large fraction (up to 95%) of the Sb atoms is found on substitutional sites. In the 25 °C implants, however, a heavily damaged region is formed around the track of each implanted Sb. At doses greater than ~1014 ions/cm2, these damaged regions overlap to produce an essentially amorphous layer, which then requires an annealing temperature of ~650 °C to reorder the lattice and to achieve a high level of ...