Diamond and Related Materials: International Journal on the Science and Technology of Diamond and Related Materials vol:8 issue:7 pages:1193-1197
A 13.56 MHz magnetically confined inductively coupled plasma (ICP) system has been applied to deposit diamond-like carbon (DLC) coatings from a methane plasma. An important advantage of using a remote plasma source over the conventional capacitively coupled parallel plate system is the possibility of decoupling the discharge power absorption and the substrate bias, allowing independent control of ion flux and energy. Five deposition parameters have been varied: the bias voltage, the r.f. power in the ICP source, the methane flow, the distance between the source and the substrate, and the cooling of the substrates. The mechanical properties of the coatings (hardness and Young's modulus) were measured by nano-indentation. The structural properties were determined by Fourier transform infrared spectroscopy and Raman spectroscopy. In addition, mass spectrometry was performed to determine the degree of dissociation of the precursor gas in the plasma. An efficient cooling of the substrates was very important to obtain higher deposition rates and slightly better quality of the coatings. It was demonstrated that the deposition rate can be substantially raised compared with the conventional capacitively coupled system, without reducing the quality of the coatings. A disadvantage of the ICP technique is the fraction of capacitive coupling from the r.f coil to the plasma, which causes sputtering of the dielectric window resulting in contamination of the coatings and deterioration of their properties. This problem was reduced by installing a Faraday shield between the coil and the dielectric window. (C) 1999 Elsevier Science S.A. All rights reserved.