Amorphous phase and anisotropy induced by glancing incident ion beams in Co-Nb films

Co-Nb amorphous films were prepared with the aid of glancing incident ion beams during deposition process. Influence of ion interaction to phase formation and fine microstructure was studied. Amorphous range is about 19 to 63 at.% Co fractions, which is wider than that obtained by perpendicular ion bombardment (28 to 68 at.% of Co fractions). A ripple or a bamboo raft pattern with nanoscale periodicity is observed in the TEM (transmission electron microscopy), SEM (scanning electron microscopy) and AFM (atomic force microscopy) images. The sizes of the image patterns are characterized by correlation length calculated from height-height correlation function (HHCF). The correlation length along the ion incidence is longer than that perpendicular to the ion incidence. Analysis regards that the glancing incident ion beams have high efficiency in both rapid cooling and ion mixing (IM). The main pattern feature in the images mainly comes from surface erosion. Other fine microstructure and the difference among the images result from surface diffusion or viscous flow effect. (C) 2008 Elsevier B.V. All rights reserved.