Temperature influence on the formation of triangular features superimposed on nanoripples produced by low-energy ion beam

Abstract

Low energy ion beam-induced nanoscale ripple patterns have attracted attention due to their use in various technological applications. Making defect free, highly regular, and low wavelength (∼30 nm) ripple patterns is still under investigation as ripple patterns form over triangular features (elevations and depressions) that curtail their use in an application. In this work using 300 eV Ar+ ion beam, the topographic evolution of such triangular features at elevated temperature up to 500 °C for ion fluences of 2 × 1018 to 1 × 1019 ions cm−2 was examined. Triangular features remain intact well up to 200 °C with a marginal decrease in the base angle. Above 300 °C, triangular features start corrugating and, finally both triangular features and ripple vanished at 500 °C. The experimental findings were compared using modified anisotropic Kuramoto-Sivanshinsky (AKS) equation by Loew and Bradley (LB) incorporating simultaneously diffusion coefficient and third order dispersion term. Temperature-induced effects are adequately replicated; dispersion produces the triangular features and diffusion helps to grow it further. In experiment base angle and lateral length of the triangles decrease with increasing temperature, similar trend was observed in numerical simulations by varying the diffusion coefficient.