Low-temperature deposition of diamond-like carbon films using a repetitive nanosecond pulsed glow discharge plasma operated in burst mode

A diamond-like carbon film with a film hardness of 12 GPa was prepared at a low substrate temperature of 60℃ using a repetitive nanosecond pulsed glow hydrogen/methane discharge plasma operated in burst mode under a gas pressure of 1.2 kPa. As the peak electrical power of the pulsed discharge increased, the hydrogen content in the films estimated by Raman spectroscopy decreased and the film hardness increased. The ion irradiation to the substrate is considered to be the main factor determining the film properties, since the hydrogen abstraction reaction and the etching of graphite components by hydrogen radical irradiation are weakened in the low-temperature deposition. (author)