Electrically Conductive Diamond-Like Carbon Coatings Prepared by Plasma-Based Ion Implantation with Bipolar Pulses

An electrically conductive diamond-like carbon (DLC) coating technique has been developed by plasma-based ion implantation with bipolar pulses. Energetic electrons and ions, which were induced by positive and negative pulses, respectively, were bombarded alternately on a substrate in C7H8 plasma. As a result, the resistivity of DLC film decreased with increasing ion energy under electron bombardment, and reached 1 m Omega cm at -20 kV. The hardness of the film was 5.4 GPa, and the hydrogen atomic concentration was 10%. TEM observation showed that the electrically conductive DLC films are composed of clusters of graphitelike aggregates. The technique can be applied for conductive DLC coatings on a three-dimensional substrate with high adhesion strength.