Synthesis of amorphous carbon films by plasma-based ion implantation using ECR plasma with a mirror field

Carbon films were synthesized on Si wafer with or without a pulse biasing and DC biasing by a plasma-based ion implantation system using an electron cyclotron resonance (ECR) plasma source with a mirror field and a power supply to apply negative high-voltage pulses and a negative DC bias to the substrate. Diamond-like carbon (DLC) films with a smooth surface and a low friction coefficient could be formed by the application of low negative-voltage pulses to the substrate, such as −2 kV; however, polymer-like carbon films were formed without pulse biasing or by only a DC biasing to the substrate. Furthermore, the tribological properties, such as friction coefficient and wear, were much improved under a high applied load during the friction test when the DLC film was formed by the simultaneous application of the pulse bias of −2 kV and the DC bias of −200 V. It is considered that the improvement in tribological properties was due to the increase in thickness of the mixed layer formed at the interface between the DLC film and the Si substrate by application of the DC bias.