Plasma-assisted CVD of hydrogenated diamond-like carbon films by low-pressure dielectric barrier discharges

Hydrogenated diamond-like carbon (DLC) films have been dep osited on silico n substrates from dielectric barrier discharge (DBD) plasmas of CH4 at room temperature under a pressure of 0.4-4.0 Ton: The effects of discharge gas pressure (P), the applied peak voltage and the distance of the discharge ga s spacing (d) on the film quality have been systematically investigated. Th e film hardness is mainly dependent on the Pd value and applied peak voltag e. The best films of phi 40-70 mm with Knoop hardness up to 20 GPa can be d eposited at 30 kV peak voltage with a Pd value of about 2 Ton mm. The depos ited films were characterized by scanning electron microscopy, Raman and FT IR spectroscopy. These analyses show that the deposited films are homogeneo us hydrogenated amorphous carbon films with very smooth surfaces containing significant amounts of sp(3) C-C bonding. The high-voltage and current wav eform measurements of the discharge indicate that the low-pressure DBD cons ists of uniform (along the whole electrode) Slow-like single breakdowns wit h half-widths of several microseconds. The DBD-induced deposition technique used in this work has many advantages, including the simplicity of the exp erimental set-up, large area deposition of DLC films and a lower consumptio n of feed gas and electric power.