Effect of N doping on structure and properties of DLC films produced by plasma beam deposition

A novel plasma beam source for the deposition of DLC films is described. Wide ranges of ion energy (130-250 eV) and C2H2/N2 flow conditions have been used to investigate the effect of N doping on the structure and properties of DLC films. The resulting films are characterized by their chemical composition, Raman spectra, electron spin density, mass density, and hardness, which critically depend on the N content. The addition of N causes the sp2 carbon content in the DLC films to increase and results in lower density and hardness. The film density also decreases with increasing ion energy at high N concentrations. Carbon films with maximum density and hardness of 2.1 g/cm3 and 25 GPa, respectively, can be produced using the plasma beam source.