Modification of surfaces following plasma implantation of helium

The surface and sub-surface regions of silicon and a range of titanium- and vanadium-based metals have been modified by implantation of helium at energies of 20-50 keV, using the Plasma Immersion Ion Implantation (PI3) facility at ANSTO. In the case of silicon, the resulting structure has been altered further, either by thermal annealing, or by thermal annealing following the application of a thin, sputtered, film of gold onto the surface. For the metals, the implanted structure has been oxidised in several ways; thermally, anodically, and by plasma implantation. Surfaces modified in these ways might be expected to have unique chemical and physical properties. They have been investigated by a range of techniques including electron microscopy, Raman spectroscopy, Rutherford backscattering spectrometry, and nuclear reaction analysis. The structure and phases of oxides developed on plasma-implanted metals are compared with those on unimplanted, but otherwise identically treated, metals. Corresponding results for helium-ion implantation at higher energies are also presented. It is shown that implantation can affect the blend of oxide phases at the surface and the degree of oxidation