Self-organized Si nanoripples induced by low-energy plasma ions

Highly-ordered silicon (Si) nanoripples with remarkable surface properties are of interest for various applications and theoretical studies. However, conventional nanopatterning techniques typically involve a limited processing area and require high energies-often reaching several hundred keV, which constrains their applicability to broader field such as thin films. Accordingly, it is necessary to develop nanopatterning processes in the low-energy regime and understand the mechanism of self-organized nanopattern formation therein. In this study, self-organized Si nanoripples were fabricated using a radiofrequency (RF)-biased inductively coupled plasma (ICP) under the low-ion energy regime. The formation and structural characteristics of the nanoripples were found to be strongly influenced by the ion energy and current density incident on the surface. The angle of ion incidence played a critical role in defining the ripple orientation: at oblique incidence angles, the ripples aligned perpendicular to the ion direction, whereas at normal incidence, randomly oriented ripples were observed. These findings provide valuable insights into plasma–surface interactions and advance the development of low-energy, self-organized nanopatterning processes suitable for broader applications.