RF-sputtered amorphous CNx for contact recording applications

Abstract

RF sputtered a-C:N films have been produced with nitrogen concentrations ranging from 2 to 40 atomic percent. The hardness of the films as measured by nanoindentation was found to linearly decrease from 32 to 13 GPa with increasing nitrogen content. Evidence for carbon-nitrogen bonding was obtained from x-ray photoelectron spectroscopy. The compressive stress level in the films increased with substrate bias reaching 3.7 GPa at an RF substrate bias of 200V. The tribological properties were evaluated using pin-on-disk scratch testing. The critical loads measured for the tested a-C:N. film was twice as great as for a comparably hard a-C:M film. Optical Surface Analyzer (OSA) optical reflectance characterization of the scratch testing demonstrated differences in failure mechanism between the a-C:N and a-C:H films.