Deposition of c-BN films by DC magnetron sputtering

Abstract

Abstract New results of the deposition of cubic boron nitride (c-BN) films by use of DC magnetron sputtering will be presented. This technique is of great interest for industrial applications, because of its high growth rates and upscaling potential. Boron carbide was used as target material with a suitable electrical conductivity for DC sputtering. The target as well as the substrate holder were connected to DC power. In the experimental set-up we used the unbalanced magnetron mode (UBM) attained with a magnetic coil surrounding the substrate table. A c-BN deposition process was developed based on a parameter transfer from a RF diode system. The c-BN content of the films will be discussed in relation to the different process parameters. Important process parameters for the formation of the cubic phase were the ion current at the substrate table and the resulting ratio of ions to neutrals. Nearly single phase c-BN films were deposited on silicon and steel substrates. The elemental film composition and the film structure were characterized by electron probe microanalysis (EPMA), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). Nanoindentation and friction coefficient measurements revealed excellent mechanical and tribological properties of the films.