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

Abstract

In this work, hydrogenated carbon films were sputter deposited at low temperatures using different Ar–CH 4 mixtures. The deposition rate of the films increases by up to a factor of 6 when comparing a CH 4-rich mixture to a pure Ar plasma. At the same time, the sp 3 carbon content is much higher when CH 4 is added to the Ar, and as a consequence the resistivity increases by approximately six orders of magnitude, and the breakdown electric field increases by approximately a factor of three. Another attractive feature of the films deposited with a CH 4-rich plasma is the low dielectric constant, down to 1.8 for a pure CH 4 plasma. The rms roughness of a 1-μm thick film is as low as 1.6 nm. All these features make this technique interesting for depositing intermetallic layers.