Tutorial: The systematics of ion beam sputtering for deposition of thin films with tailored properties

Abstract

There is an increasing demand for thin films with tailored properties, which requires the use and control of adequate deposition techniques. Ion beam sputter deposition (IBSD) is a physical vapor deposition (PVD) technique that is capable of fulfilling the technological challenges. In contrast to other PVD techniques, IBSD offers a unique opportunity to tailor the properties of the film-forming particles (sputtered target and scattered primary particles) and, hence, thin film properties. This is related to the fact that the generation and acceleration of the primary particles from the ion beam source, the generation of film-forming particles at the target, and thin film growth on the substrate are spatially separated. Thus, by changing ion beam parameters (ion species and ion energy) and geometrical parameters (ion incidence angle and emission angle), the energy distributions of the film-forming particles are modified. Even though in use for several decades, IBSD was not investigated systematically until lately. Utilizing the full potential of IBSD requires a comprehensive understanding of the physical processes. This tutorial describes the systematics of IBSD: The correlation between process parameters, properties of the film-forming particles, and thin film properties. The most important process parameters are the scattering geometry and the primary particle species. Depending on the material, different film properties can be influenced. Examples are adhesion, structural properties, composition, surface roughness, mass density, optical properties, stress, and electrical resistivity. In addition to the experimental results, fundamental physical aspects, experimental setups, and techniques for thin film deposition and particle characterization are described.