DIAMOND-LIKE COATINGS - MICROSTRUCTURAL EVOLUTION UNDER ION-BEAM ASSISTANCE

Non-hydrogenated diamond-like carbon films have been prepared by Dual Ion Beam Sputtering and Ion Beam Assisted Magnetron. The assistance pa rameters -ion energy, ion mass, ion flux/atom flux- have been systemat ically varied and their effect on the microstructure of the films stud ied. The films have been characterised by Rutherford Backscattering Sp ectroscopy (RBS), High Resolution Transmission Electron Microscopy (HR TEM), Electron Energy Loss Spectroscopy (EELS), Positron Annihilation Spectroscopy (PAS), and Raman Spectroscopy (RS). RBS and PAS results s howed that the density and the degree of disorder of the films go thro ugh a maximum with ion energy, and that the void concentration goes th rough a minimum. EELS and RS show that the films are mostly sp(2) bond ed, with a maximum concentration of sp(3) bonding of about 16% for the largest values of density. The evolution of density with ion flux and energy is consistent with a combined effect of atomic displacements i n the film leading to densification, and with damage buildup leading t o progressive graphitisation as the energy is increased.