Mechanical properties of diamond like carbon coatings prepared by microwave electron cyclotron resonance plasma chemical vapour deposition process

Abstract

Diamond like carbon coatings were deposited on Si (111) substrates under the influence of dc bias developed on the substrates by application of 13.56 MHz rf, using fixed ratio of flow rates of argon and methane gases. The deposited coatings were characterized by Raman spectroscopy that confirms the presence of DLC in deposited coatings. FTIR characterization was done to investigate the C-H bonding in the coatings. Mechanical properties such as Young's modulus (E), hardness (H) and critical load (Lc) for coating delamination have been determined through use of nanoindentation and nanoscratch techniques. The effect of the substrate bias voltage on the mechanical properties of the deposited DLC films is studied. The results indicate that mechanical properties of DLC are sensitive to the bias applied to substrate and there is an optimum substrate bias voltage for deposition of the coatings with desirable properties.