NEXAFS study of DLC films prepared by Ar cluster and monomer ion assisted deposition

Diamond Like Carbon (DLC) films were formed by Ar cluster ion beam assisted vapor deposition of C₆₀. To study the effects of contaminating Ar monomer ions (Ar) in the cluster beam on the sp² content, film hardness, and surface morphology of the films, beams of Ar cluster ions, Ar⁺, and a mixture of cluster ions and Ar⁺ were used for the bombardment, during evaporation of C₆₀. From the Near Edge X-ray Absorption Fine Structure (NEXAFS) and Raman spectroscopy measurements, lower sp² contents in carbon films were obtained for the cases when Ar cluster ion beams were used. The usage of single Ar+ and mixed ion beams showed higher sp² contents. Furthermore, higher hardness and smoother surfaces were obtained with Ar cluster ion irradiations. Therefore, the increase of the fraction of Ar cluster ions in the beams was important to obtain hard DLC films with flat surfaces.