Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

Ultrathin (<5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gb/in(2). These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry if the "macroparticle" issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system-a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using S-filter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested.