Study of diamond-like carbon films for protective coatings

Abstract

Interest in investigating thin films of diamond-like carbon (DLC, a-C:H) has been motivated by the unique properties of this material and the demand of modern technologies. The development of low-temperature methods T3 s < 200 °C) for producing DLC films used as protective layers is of practical interest. In this work, a-C:H films were prepared by low-temperature deposition by using three methods: magnetron-sputtering of a graphite target in argon (80%)-hydrogen (20%) atmosphere, magnetron sputtering of graphite target combined with plasma-stimulated, gas-phase deposition from a mixture of gases (10% CH 4 + 90% Ar) and rf decomposition of a mixtures of gases (10% CH 4 + 90% Ar). A comprehensive investigation of the composition, structure, optical and electrical properties of a-C:H films was performed from the standpoint of the requirements that protective coatings for electrophotograhic information carriers and stable protector for Ag-based optics must meet. The investigation of the composition and structure was performed by elastic recoil detection (ERD), resonance nuclear reaction 16O (α, α) 16O and Raman spectroscopy. The optical properties (the transparency over a wide spectral range and the refractive index) were determined by means of IR-spectroscopy and ellipsometric measurements. It was shown that solid, diamond-like a-C:H films (DLC) can be obtained with low-temperature deposition. It was shown that a protective DLC coating increases the storage time in the air and the strength properties of the a-Se (or a-Se alloy) electrophotographic information carriers. It was determined that a protective DLC coating is an effective and stable protector for Ag-based optics from an attack of active sulfide.