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Ion bombardment (IB) is a promising nanofabrication tool for self-organized nanostructures. When ions bombard a nominally flat solid surface, self-organized nanoripples can be induced on the irradiated target surface, which are called intrinsic nanoripples of the target material. The degree of ordering of nanoripples is an outstanding issue to be overcome, similar to other self-organization methods. In this study, the IB-induced nanoripples on bilayer systems with enhanced quality are revisited from the perspective of guided self-organization. First, power spectral density (PSD) entropy is introduced to evaluate the degree of ordering of the irradiated nanoripples, which is calculated based on the PSD curve of an atomic force microscopy image (i.e., the Fourier transform of the surface height. The PSD entropy can characterize the degree of ordering of nanoripples). The lower the PSD entropy of the nanoripples is, the higher the degree of ordering of the nanoripples. Second, to deepen the understanding of the enhanced quality of nanoripples on bilayer systems, the temporal evolution of the nanoripples on the photoresist (PR)/antireflection coating (ARC) and Au/ARC bilayer systems are compared with those of single PR and ARC layers. Finally, we demonstrate that a series of intrinsic IB-induced nanoripples on the top layer may act as a kind of self-organized template to guide the development of another series of latent IB-induced nanoripples on the underlying layer, aiming at improving the ripple ordering. The template with a self-organized nanostructure may alleviate the critical requirement for periodic templates with a small period of ~100 nm. The work may also provide inspiration for guided self-organization in other fields. [ABSTRACT FROM AUTHOR]

• Energy dependence of resist morphology under ion bombardment is demonstrated. • Light molecules in organic resist were enriched by ion bombardment. • Ion energy shows great potential for modulating chemistry and morphology. • Nanoholes were formed on organic resist in a wide ion energy range. • Morphology evolution is preliminarily explained using existing theoretical models. The energy dependence of nanostructures on a photoresist produced by ion bombardment (IB) under normal incidence is studied through atomic force microscopy and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The energy-dependent morphology evolved from weak islands via nanoholes to a smooth surface on the resist; in particular, nanoholes were produced for a broad energy range of 300–550 eV. The enrichment of light components in the surface layer of the irradiated resist was illustrated owing to the strong decomposition of the photoresist by IB. The energy dependence of the morphologies is explained according to the ToF-SIMS characterization and the existing theoretical models of IB, which is an IB-induced synergy of chemical variation and sputtering. This study extends the IB in inorganic materials into an organic-multicomponent photoresist and provides new insights into the experimental evidence for nanoholes and possible parameters to improve the relevant theoretical model. [ABSTRACT FROM AUTHOR]