Hydrogenated diamond-like carbon film prepared by RF bias assisting magnetron sputtering

Magnetron sputtering is an efficient way to deposit hard coatings in industry. However, as for hydrogenated diamond-like carbon (DLC:H) film, the low ionization rate of reaction gases causes poor mechanical properties. Here, in order to improve the ionization rate of C₂H₂ during depositing DLC:H, a radio frequency (RF) bias assisting magnetron sputtering system was elaborated. With increasing the RF bias voltage, the fullerene in the amorphous carbon are disappeared, accompanied with decrease of hydrogen content and increase of the sp3C ratio. DLC:H film with a hardness of 33 GPa is successfully deposited, and its elastic recovery is over 75%. The high mechanical properties of DLC:H is mainly due to the high sp³ C ratio, which is primarily contributed by the enhanced ionization of the RF bias. This paper suggests that the RF bias assisting magnetron sputtering is an economical and efficient method to deposit DLC:H with superior mechanical property, and it is promising for industrial mass production.