An apparatus for glancing incidence ion beam polishing and characterization of surfaces to angstrom-scale root-mean-square roughness

An instrument is described which combines a glancing incidence ion beam erosion system with a scanning tunneling and an atomic force microscope. This instrument allows the ion beam polishing and surface topographic characterization of conducting and insulating, crystalline, polycrystalline, and amorphous samples under ultrahigh vacuum conditions. As an illustration of the capability of the instrument and the polishing technique, we present results demonstrating a fivefold improvement in rms roughness of a polycrystalline Cr film and a fivefold reduction in rms roughness of a vicinal, initially mechanically polished CaF2 (111) sample. The final rms roughness of the latter sample of 0.12 +/- 0.04 nm measured over the bandwidth of 10-500 nm is just 75% of the Ca-F interlayer spacing for the (111) surface orientation. (C) 1996 American Institute of Physics.