Synthesis of Ultrathin Ta-C Films by Twist-Filtered Cathodic Arc Carbon Plasmas

Abstract

ABSTRACTThe application of cathodic-arc-deposited films has been very slow due to the infamous macroparticle problem. We report about the application of the open Twist Filter as the key component to an advanced filtered cathodic arc system. Ultrathin tetrahedral amorphous carbon (ta-C) films have been deposited on 6 inch wafers. Film propertieshave been investigated with respect to application in the magnetic data storage industry. Films can be deposited in a reproducible manner where film thickness control relies on arc pulse counting once deposition rates have been calibrated. Films of 3 nm thickness have been deposited that passed acid and Battelle corrosion tests. Monte Carlo Simulation of energetic carbon deposition shows the formation of an intermixed transition layer of about 1 nm. The simulation indicates that because the displacement energy of carbon isnot smaller than of magnetic materials, films thinner than 2 nm are either not high in sp3 content or represent a carbidic phase.