Evolution of periodical surface nanostructures under off-normal gas cluster ion irradiation

Abstract

Gas cluster ion beam is known as a tool for surface smoothing; at the same time, surface relief formation under oblique beam incidence was reported. We suggested using samples with pre-formed surface pattern to study its evolution caused by ion irradiation and applied this approach to reveal the mechanisms responsible for nanorelief developing under off-normal cluster ion incidence. The role of key processes, which are ballistic diffusion and sputtering depending on the local incidence angle and surface curvature, is discussed. The irradiation conditions as well as the initial patters found to influence on the resulting surface shape.