Preparation of ultra-thin carbon overcoat for magnetic recording medium by filtered cathodic vacuum arc technology

Abstract

The deposition process of carbon coating by filtered cathodic vacuum arc (FCVA) system was studied for the development of a high-density magnetic disk with an ultra-thin overcoat of about 2 nm thickness. A FCVA system was installed on disk production equipment for the deposition of carbon thin coating on the disk sample. The FCVA method, processed at a low pressure of 10 −4 Pa, using no reactant gas, had some advantages over the plasma CVD method in deposition of the hard carbon thin coating on an electrically floated substrate. The carbon coating of less than 3 nm in thickness was examined for the various properties with respect to the coating requirements for magnetic recording media. The properties of this ultra-thin coating were the same as those of a relatively thick tetrahedral amorphous carbon (ta-C) film. Moreover, the injection of the energetic ions from the arc source formed a mixture layer on the surface of the magnetic film. Several effective measures were proposed to avoid the deterioration of the magnetic properties.