Characteristics of amorphous carbon films prepared by hybrid RF (195 kHz) plasma triggered by shunting arc discharge

Hybrid plasma was generated by combining a burst methane radio frequency (rf) (195 kHz) plasma with a carbon shunting arc discharge. The methane rf plasma was triggered by the shunting arc discharge over a wide range of ambient gas pressures from as low as 0.045 Pa as a baseline pressure to a methane pressure of 0.84 Pa, which prevented the rf plasma from self-igniting. When a target was immersed in the rf- and shunting arc-hybrid plasma and a negative pulse voltage was applied to a disc electrode, carbon ions were extracted from the hybrid plasma and an amorphous carbon film was deposited on a silicon substrate mounted on the disc electrode. The carbon shunting arc significantly increased the ionisation of the methane gas initiated by the rf plasma. The plasma density in the hybrid plasma increased by a factor of 5–9 compared to that of the shunting arc discharge alone. The deposition rate of the carbon film also increased by adding the rf plasma component. The prepared films showed an amorphous structure characterised by D- and G-peaks in the Raman spectrum.

► A hybrid plasma of methane rf and carbon shunting arc was produced. ► Ion density increased by a factor of 5–9 with hybridizing the both plasmas. ► Deposition rate of carbon film increased with hybridizing the plasmas.