Hydrogenated amorphous carbon (a-C:H) films were deposited on silicon wafers using a pseudo-spark discharge (PSD) method. A mixture of argon and acetylene (C2H2) was employed as the process gas. PSD generates high-density plasma and forms a diffuse discharge due to the hollow cathode effect. The film structure was analyzed using Raman spectroscopy, while film hardness was measured using nanoindentation. Surface hybridization states and contamination levels were examined by X-ray photoelectron spectroscopy. This study investigates the optimal distance between the anode and the deposition substrate, as well as the optimal flow rate ratio using acetylene diluted with argon. The results indicated that the optimal substrate distance was 40 mm and the ideal flow rate ratio (Ar/(Ar + C2H2)) was 1%. Under these conditions, the a-C:H films exhibited a G-band position of 1,571 cm−1, a full width at half maximum of 114 cm−1 for the G peak, a deposition rate of 155 nm/h, and a hardness of 5.3 GPa.
Kamada et al. (Thu,) studied this question.