Morphological instabilities in argon ion sputtered CoSi binary mixtures

Abstract

Nanopattern formation on CoxSi1−x ( << x 01) surfaces has been studied under a range of low energy Ar+ ion bombardment at oblique incidence and also at varying ion fluences. Our study shows a clear morphological change for the nanostructures depending upon the incident beam energies and binary mixture stoichiometries. From an initial smoothening regime, well-ordered nanoscale ripples form at sub-keV energies at ion fluences ∼ 1018 ions cm−2. These ripples further transform into micrometer-sized ellipsoidal structures upon increasing the ion energy from500eVto 1200eV. Thewavelengths ofthe nanostructures increasewith ion fluence obeying a power law behaviour f0.123, where f is the fluence. For higher values of Co content, the rippled morphology is gradually replaced by bug-like hierarchical structures.