Deposition of DLC films in CH4/Ne and CH4/Kr rf plasmas

The deposition of a hydrogenated diamond-like carbon (DLC) film and plasma diagnostics were carried out in 13.56 MHz r.f. CH4/Ne and CH4/Kr plasmas. The mechanical and optical properties of the deposited DLC films were examined with respect to the source gas composition ratio. The film deposition rates, depending on the CH4 content of the plasmas, indicated almost the same behavior. On the other hand, the mechanical hardness of the films was different; it slightly increased with decreasing CH4 content in CH4/Ne plasma, whereas it decreased monotonically in CH4/Kr plasma. This result is consistent with the IR absorption spectra of the films. Mass spectrometry measurements of the plasma were carried out, and the ionic species reaching the electrode were determined. The Ne and Kr admixtures enhanced hydrocarbon ion densities in both plasmas via deexcitation processes. (C) 1997 Elsevier Science S.A.