The fabrication and growth mechanism of AlCrFeCoNiCu0.5 HEA thin films by substrate-biased cathodic arc deposition

Abstract

AlCrFeCoNiCu0.5 thin films were fabricated by cathodic arc deposition under different substrate biases. Detailed characterization of the chemistry and structure of the film, from the substrate interface to the film surface, was achieved by combining high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Computer simulations using the transport of ions in matter model were applied to understand the ion surface interactions that revealed the key mechanism of the film growth. The final compositions of the films are significantly different from that of the target used. A trend of elemental segregation, which was more pronounced with higher ion kinetic energy, was observed. The XPS results reveal the formation of {mathrm{Al}}_{2}{mathrm{O}}_{3} and {mathrm{Cr}}_{2}{mathrm{O}}_{3} on the thin film surface. The grain size is shown to increase with the increasing of the ion kinetic energy. The growth of equiaxed grains contributed to the formation of a flat surface with a relatively low surface roughness as shown by atomic force microscopy.