Comparative Study on Chemical Vapor Deposition of Diamond-Like Carbon Films from Methane and Acetylene Using RF Plasma

Abstract

Diamond-like carbon films (DLC) were prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) at a frequency of 13.56 MHz using methane (CH4) and acetylene (C2H2) at different RF powers. Optical emission spectroscopy (OES) was carried out to investigate plasma chemistry. The intensity of Hα in the C2H2 plasma was about one-half that in the CH4 plasma, whereas in both cases, the intensities of CH radicals were similar. The resistivity of the deposited films decreased with an increase in RF power, whereas growth rate increased with RF power. CH4-based films were found to be more insulating than C2H2-based films at high RF powers. The high resistivity of the films was obtained from both CH4 and C2H2 at low RF powers. The insulating property was due to the hydrogenation of sp2 bonds in the films.