HARDNESS AND YOUNG MODULUS OF DIAMOND-LIKE CARBON-FILMS PREPARED BY ION-BEAM METHODS

Amorphous diamond-like carbon films were prepared in a dual ion beam facility equipped with two Kaufmann sources of 3 cm diameter and of a maximum beam voltage of 1500 eV. Films were prepared: (i) by sputtering carbon atoms from a graphite target and assisting the deposition process with an Ar+ and H+ ion beam of variable mixture and energy; (ii) by direct deposition using methane as the working gas without the assistance of a second ion beam. Hardness and Young's modulus of the films were determined with a depth-sensing ultralow-load nanoindentation method. The atomic hydrogen content was determined by FTIR spectroscopy from the integrated absorbance of the CH stretching modes. The values were absolutely calibrated by ERD measurements. The sp3 sp2 bond ratio of hydrogen atoms was determined from an analysis of the individual components of the CH stretching modes. The chemical composition of the films was determined by RBS. Films of atomic hydrogen content, x < 5% displayed values for hardness up to 57 GPa and Young's modulus up to 335 GPa. It was observed that hydrogen content is the most significant parameter for hardness, Young's modulus, density and and the sp3 sp2 ratio, whereas the energy, EA, supplied to a condensing C-atom plays a major role only for x < 5%. © 1992.