Techniques for filtering graphite macroparticles in the cathodic vacuum arc deposition of tetrahedral amorphous carbon films

Filtered cathodic vacuum are (FCVA) deposition has been found to be a reliable technique for the production of high quality tetrahedral amorphous carbon films (ta-C). These coatings can be used as protective coatings for different applications ranging from cutting tools to human hip joint prosthesis. The FCVA technique is widely used in different laboratories around the world with somewhat different technical implementations. A serious disadvantage in the FCVA technique is the graphite particles that are emitted from the solid graphite cathode during the are-discharge. A variety of different techniques exist to diminish their production and transport. However, some of the magnetic filtering designs that are used to reduce the macroparticle transport into the substrate do not work well with high melting point cathode materials such as graphite. Although the influence of graphite particles for the ta-C coating performance in some applications is controversial, many applications demand that the produced ta-C film is practically particle-free. This is especially important in corrosion resistance, electrical and optical applications. In this paper an introduction to different FCVA devices is presented. Different magnetic filtering designs together with control techniques for macroparticle generation have been reviewed and their advantages and disadvantages in the plasma transport and particle filtering efficiency have been discussed. (C) 1999 Elsevier Science S.A. All rights reserved.