Ion beam sputtering nanopatterning of thin metal films: the synergism of kinetic self-organization and coarsening

Creation of self-organized surface nanostructures by ion beam sputtering (IBS) has strong potential for use in a broad range of technologies, from nanoelectronics and photonics to sensing and catalysis. Recently, we have developed a simple two-stage process for fabricating self-assembled arrays of Cu dots and lines on Si and SiO2 substrates employing IBS of thin Cu films. We found that the self-assembled structures on the substrate result from a complex interaction between the structure-forming kinetic instability and various outcomes of the surface diffusion and coarsening, which tend to drive the surface pattern towards a thermodynamic equilibrium. Here, we analyze in detail the interplay of the kinetic nanopatterning and coarsening, in order to better understand the mechanisms defining the IBS-generated metallic structures on substrates of a different material. By means of kinetic Monte Carlo (KMC) modeling we investigate the pertinent trends of the self-organization at the surface of a metallic film. In the light of this discussion, we review the fabricated nanostructures. Finally, we present a KMC model of the two-stage IBS process and analyze the stability of the fabricated metal patterns at the surface of a substrate. We discuss the opportunities and challenges of this technique, concluding that the IBS creation of surface heterostructures provides considerable room for future numerical and experimental studies.