THE EFFECT OF ION ENERGY ON THE DIAMOND-LIKE GRAPHITIC (SP(3)/SP(2)) NATURE OF CARBON-FILMS DEPOSITED BY ION-BEAMS

Ion energy is known to be a crucial parameter in the determination of properties of films deposited by ion beams. Contradictory results regarding the optimal C ion energy for the deposition of diamond-like (sp3-rich) carbon films have been reported: (i) about 20-40 eV by McKenzie et al., (ii) about 100-200 eV by Ishikawa et al. and (iii) about 100-700 eV by Hirvonen et al. These data are important both for establishing models of carbon film growth from ion beams and for practical film depositions. In the present work pure carbon films were deposited at room temperature on Si using mass-selected C+ ions covering the energy region 10-300 eV. Diamond-like properties were found for the entire energy region 30-300 eV. A transition to graphitic properties was observed for ion energies lower than 30 eV.