Carbon Nitride Formation by Plasma Assisted Ion Beam Deposition

Abstract

Theoretical works have indicated that carbon nitride, in a β-C₄N₄ phase, would have optical and mechanical properties comparable to or exceeding those of diamond. In this effort, the formation of carbon nitride thin films was investigated using a Plasma Assisted Ion Beam Deposition (PAIBD). In this technique, a C^- ion beam combined with a N₂ or NH₃ RF plasma source is used to synthesize carbon nitride films. These films were investigated as a function of both C^- ion beam energy and the power of the plasma source. The C^- ion energy was found to be a key parameter in the formation of carbon nitride. The films were evaluated by a variety of diagnostic techniques including Raman, AES, XRD and FTIR. Analysis confirms high nitrogen concentration in the synthesized films and the major portion of carbon being single bonds in the sp³ bond configuration, which is a characteristic of the tetrahedral -C₃N₄ phase. Tribology tests confirmed that the friction coefficient and the wear rate are comparable to diamond. The results show that the higher C^- ion beam energy (-150 eV) forms insulating films with the highest single bond percentages in the range studied. We believe beam energy control is critical to the types of bonds formed.