A LOW-ENERGY ION IMPLANTER FOR SURFACE AND MATERIALS SCIENCE

A low-energy ion-beam facility for surface and materials science has b een built which allows ion beam treatments of solid surfaces via singl e-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 s pread is estimated to be as small as 2 eV in the whole range. Ion curr ent densities are available in the range between 0.1 nA/cm(2) and up t o 50 mu A/cm(2), corresponding to a particle flux of 10(9)-10(14) ions /cm(2) s. Homogeneous implantation profiles are achieved using an elec trostatic x-y deflection system. First applications for ion induced de fect production on highly oriented pyrolytic graphite surfaces detecte d via scanning tunneling microscopy are presented. Hillock shaped defe ct formations were detected and attributed to protusions of the atomic surface structure, which were induced by interstitials and interstiti al clusters between the first atomic planes originated from recoil ato ms of the collision cascade. (C) 1998 American Institute of Physics.