Effects of the methane content on the characteristics of diamond-like carbon films produced by sputtering

In this work, hydrogenated carbon films were sputter deposited at low tempe ratures using different Ar-CH4 mixtures. The deposition rate of the films i ncreases by up to a factor of 6 when comparing a CH4-rich mixture to a pure Ar plasma. At the same time, the sp(3) carbon content is much higher when CH4 is added to the Ar, and as a consequence the resistivity increases by a pproximately six orders of magnitude, and the breakdown electric field incr eases by approximately a factor of three. Another attractive feature of the films deposited with a CH4-rich plasma is the low dielectric constant, dow n to 1.8 for a pure CH4 plasma. The rms roughness of a 1-mum thick film is as low as 1.6 nm. All these features make this technique interesting for de positing intermetallic layers. (C) 2000 Elsevier Science S.A. All rights re served.