Nanofabrication of self-organized periodic ripples by ion beam sputtering

Ion beam sputtering of solid surfaces with ions of low keV energies can produce self-organized periodic ripple patterns of nanometer size on the surface of semiconductors, metals and insulators, therefore looking to be a single-step, cost-effective method to fabricate surface topographies over large areas for various electronic and bio-devices.
To date, a comprehensive theoretical understanding of the ripple development is still missing, and the achievement of the application-specific surface topography still relay on properly tuning different ion-beam parameters, since the experiments have highlighted the dependence of ripple characteristics on them.
The success of technological applications often requires an a-priori defined ratio of ripple height to wavelength. Here we discuss how to obtain regular ripples of height h~10 nm and wavelength λ<=50 nm on silicon surfaces. Xe+ and O+ ions were used to also investigate the role of the surface chemical reactivity.
The results show the development of regular ripples with wavelengths of ~40 nm and heights of ~2 nm superimposed on a less regular periodic topography for O+ bombardment on Si; the Xe+ on Si bombardment produced structures of regularity below the expected values. We discuss the gained insights and the best recipe for the required nano-patterns.