Ion beam sputtering induced nanostructuring of polycrystalline metal films

The development of fine scale nanostructures in polycrystalline metal films by off-normal ion beam sputtering (IBS) follows similar mechanisms to those in random targets, i.e. the pattern results from the interplay of curvature-dependent-roughening and various smoothing processes. By grazing angle IBS of the deposited metal films it is possible to fabricate metallic nanoripples, nanowires, and nanorods onto semiconductor or insulator substrates without using a template. It has been found that the rms roughness of the as-deposited film is substantially reduced under ion bombardment before the development of nanoscale patterns. The structural anisotropy of the sputtered morphology can have a great influence on the local physical properties of the underlying material. In this paper, we shall review the experimental results on the formation and characteristics of the IBS ripples on polycrystalline metal films prepared by the physical vapor deposition (PVD) technique.