Dependence of hybridizations analyzed by XPS and visible Raman spectroscopy on nanohardness and wear resistance of amorphous carbon and carbon nitride films

Abstract Amorphous carbon (a-C) and carbon nitride (a-CNx) thin films were synthesized on Si (100) substrates by shielded arc ion plating (SAIP) using high purity argon or nitrogen gases, respectively, with applying a substrate bias voltage between 0 and −500 V. Nanohardness and wear resistance of the films has been measured by a nanoindenter interfaced with an atomic force microscope. When an a-C film was synthesized at −100 V of substrate bias voltage (Vb), this film showed a maximum hardness approximately 42 GPa. However, an a-CNx film with maximum hardness of 21 GPa was synthesized at −300 V of Vb. The a-C film prepared at a Vb of −100 V showed the best wear resistance. Regardless of substrate bias voltages, all of the a-CNx films showed better wear resistant properties than quartz and glass. The application of proper substrate bias voltage increased the fraction of sp3 C configuration in the a-C film and led to cross-linking between graphite-like layers due to nitrogen in the a-CNx film.