Attempt of Deposition of Ag-Doped Amorphous Carbon Film by Ag-Cathode DC Plasma with CH₄ Flow

A simple DC plasma apparatus having large Ag cathode with CH₄ flow was used for the attempt to prepare Ag-doped amorphous carbon film. As the gaseous source, CH₄ and the additive (N₂ or Ar) were used for the plasma process. When N₂ was the additive, the substrate surfaces after the plasma process were electrical conductor although high electrical resistance. The growth rate of the deposits decreased with increasing the amount of N₂, and the deposits contained nitrogen. Although the small amount of silver was detected by XPS, the peak for Ag may not be in the carbon deposit but be in interlayer formed at Ar etching process. When Ar was the additive, the substrate surfaces after the plasma process were also electrical conductor although high electrical resistance. The growth rate of the deposits was almost independent of the amount of Ar, and the deposits contained no argon. The small XPS peaks for Ag may not be in the carbon deposit but be in interlayer formed at Ar etching process. Both the prepared samples had high antibiotic property. The method of this study could be used for the surface reforming with amorphous carbon coating having electrical conductivity and antibiotic property.