Coating diamond-like carbon films on polymer substrates by inductively coupled plasma assisted sputtering

Abstract

In this paper, a new sputtering technique for coating hydrogen-free diamond-like carbon (DLC) films on polytetrafluoroethylene (PTFE) substrates in an inductively coupled plasma (ICP) will be reported. The ICP has the advantages of producing high-density plasma (HDP) for DLC deposition at low substrate temperatures (<50°C). The method developed in this work is particularly advantageous for coating on substrates with low melting points such as polymers. Various characterization techniques have been used to investigate the chemical, tribological, and electronic features of the deposited films. Raman spectroscopy revealed two broad peaks at 1386cm−1 and 1573cm−1 corresponding to the D and G peaks respectively. The DLC films produced by this method have less than 20% sp3 carbon bonds. The average grain size of the hydrogen-free DLC was ~57nm. The roughness of the uncoated PTFE substrate surfaces decreased dramatically (from 662 to 179nm) with DLC coating.