Epitaxial Growth of Ni on Si by Ion Beam Assisted Deposition

Abstract

Epitaxial Ni films were grown on Si(111) substrates to a thickness of about 500 nm by ion beam assisted deposition at room temperature. The films were grown using 25-keV-Ni ions and electron-beam evaporation of Ni at a relative arrival ratio of one ion for every 100 Ni vapor atoms. The ion beam and evaporant flux were both incident at 45° to the sample surface. Standard θ-2θ X-ray diffraction scans revealed the extent of crystallographic texture, while Ni {220} pole figure measurements identified the azimuthal orientation of Ni in the plane of the film. Films grown without the ion beam consisted of nearly randomly oriented fine grains of Ni whereas with bombardment the Ni (111) plane was found parallel to the Si (111) plane. In all the epitaxial cases the Ni [110] direction was perpendicular to the axis of the ion beam, suggesting that the azimuthal orientation of the film was determined by channeling of the ion beam down {110} planar channels in the Ni film. Additional experiments with different ions, energies, and substrates revealed their influence on the degree of epitaxy obtained.