A low-energy ion implanter for surface and materials science

Abstract

A low-energy ion-beam facility for surface and materials science has been built which allows ion beam treatments of solid surfaces via single-ion impacts up to high-fluence implantations. The system offers mass-separated ion beams of 0.5–10 keV by a normal acceleration, and of 5–2000 eV by an acceleration/deceleration lens combination. Its energy spread is estimated to be as small as 2 eV in the whole range. Ion current densities are available in the range between 0.1 nA/cm2 and up to 50 μA/cm2, corresponding to a particle flux of 109–1014 ions/cm2 s. Homogeneous implantation profiles are achieved using an electrostatic x-y deflection system. First applications for ion induced defect production on highly oriented pyrolytic graphite surfaces detected via scanning tunneling microscopy are presented. Hillock shaped defect formations were detected and attributed to protusions of the atomic surface structure, which were induced by interstitials and interstitial clusters between the first atomic planes originated from recoil atoms of the collision cascade.