Characterization of microstructure and surface properties of GLC film deposited in plasma nitriding system

Graphite-like carbon films were deposited on silicon substrates in plasma nitriding system with propane and hydrogen. Scanning electron microscope, X-ray photoelectron spectroscopy, Raman spectroscopy, atomic force microscope, and contact angle measurement method were used to investigate the effect of voltage, duty cycle, and gas composition on the growth thickness, hydrogen content, atomic bond structure, surface roughness, surface morphology, and wettability of the films. It is shown that the thickness of the films decreased with the voltage and duty cycle increasing. The voltage, duty cycle and gas composition have a significant effect on the sp2/sp3 bonds and hydrogen content, which can produce the a-C:H films characterized by sp2 bonding (over 70%). As the voltage and duty cycle improved, the surface morphology of the film progressed from a rugged surface with wide hillsides to a flat level surface. This work will provide a novel method to produce graphite-like carbon films with lubricating and anti-wear properties and give direction on designing high-performance tribosystems for industrial applications.