Carbon film deposition by powerful ion beams

Elseiver. Surface and Coatings Technology xx (2007) xxx–xxx
Carbonaceous thin films can be used in microelectronics, superconductors, solar batteries, logic and memory devices, and to increase processing tool wear resistance, and as magnetic nanocomposite materials for information storage. This paper presents a study of carbonaceous thin films deposited on silicon substrates using ablation plasma generated by pulsed power ion beams (H+—60%, C+—40%, E=500 keV, τ=100 ns, density=8 J/cm2) on graphitic targets. The concentrations of sp3-bonded crystalline diamond, and amorphous and crystalline phases of carbon were determined by X-ray diffraction analysis (XRD). It was observed that the concentration of the crystalline diamond phase in films deposited under various conditions did not exceed 5%. A substantial concentration (30–95%) of the carbon crystalline phase is in the form of C60 and C70 fullerenes. It is shown that the concentration of fullerenes and the ratio between the relative amounts of C60 and C70 greatly depends on the graphitic target density, carbon film deposition conditions and above all on the distance from the graphitic target to the silicon substrate. This distance determines the film deposition rate and the degree of cooling of the plasma generated on the substrate, which can cause changes in film crystallization conditions.