Ion Scattering Spectroscopy (ISS)

The Kratos Axis Ultra system is also equipped with facilities for Ion Scattering Spectroscopy (ISS).

ISS is a technique where a beam of ions (typically He+ or Ar+) is directed at the surface of interest and are scattered from the atoms in a surface.  As the ions lose kinetic energy, their resultant kinetic energy is measured and a spectrum is produced where peaks are observed at different kinetic energies related to the mass difference between the ion and the atom. Clearly two atoms in a surface that have very different masses (e.g. oxygen and iron) will scatter ions differently.

ISS is extremely surface sensitive, with only the top-most atomic layer being probed.  Disdvantages of ISS are the extreme sensitivity to surface contamination layers and multiple elements may be difficult to resolve in a single spectrum

    How can ISS help?

   Common applications?

  • Detection of top most surface elements
  • Measurements of adsorbed species on single crystal surfaces
  • Relative coverage determination of given elements
  • Following layer growth in-situ in areas such as ALD and indication of monolayer coverage of a surface