C–Ti nanocomposite thin films: Structure, mechanical and electrical properties

• Published in: Vacuum 2007-10, Vol.82 (2), p.214-216
• Main Authors: Sedláčková, K., Ujvári, T., Grasin, R., Lobotka, P., Bertóti, I., Radnóczi, G.
• Format: Article
• Language: English
• Subjects: Carbon nanocomposite; Hardness; Temperature dependence of resistivity; Transmission electron microscopy
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2007.07.055

Carbon–titanium nanocomposite thin films were deposited by DC magnetron sputtering on oxidized silicon substrates in argon. The films were prepared at different deposition temperatures between 25 and 800 °C. Transmission electron microscopy was used to determine the structure of the films. All the C–Ti nanocomposites consisted of columnar TiC structure with average column width ∼10 and 20 nm and a thin carbon matrix. The thickness of the carbon matrix between adjacent TiC columns was ∼2–5 nm. Mechanical properties (hardness, reduced modulus) of C–Ti films showed a distinct variation depending on the deposition temperature. Films deposited at 200 °C had the highest hardness ∼18 GPa and the highest reduced modulus ∼205 GPa. Temperature dependence of the film resistance was measured between 80 and 330 K. C–Ti nanocomposites have a non-metallic conduction mechanism characterized by a negative temperature coefficient of resistivity (TCR). The most negative TCR was observed for films showing high hardness and reduced modulus of elasticity.