Open Access Conference Proceedings

We propose the sputtering deposition providing titanium thin films with controlled properties such as preferential crystallography and residual stress using Kaufman ion-beam source. The titanium thin films with thickness of ≈ 80 nm were deposited on [001] Si wafer covered by SiO2 deposited by plasma-enhanced chemical vapor deposition. To achieve the required crystallography and stress properties, we investigated the different beam voltage of Kaufman ion-beam source and controlled the substrate temperature during deposition using a built-in heater. We used two X-ray diffraction methods to determine the planes parallel to the sample surface and residual stress. We also measured the current-voltage curves to determine the resistivity (ρ) and the thermal coefficient of resistivity (α) of titanium thin films at different substrate temperatures using 4-probe measurement setup. We showed that it is possible to prepare stress-free titanium thin films with pure [001] orientation at the lowest beam voltage of 200 V and substrate temperature of ≈ 273 °C. The corresponding lattice parameters a0 and c0 were (2.954 ± 0.003) Å and (4.695 ± 0.001) Å, respectively. Electrical parameters of this sample as ρ and α were (9.2 ± 0.1)∙10-7 Ω∙m and (2.6 ± 0.2)∙10-3 K-1, respectively. We found out that these layers are well suitable for micro-electro-mechanical systems where the pure [001] orientation, no residual stress and low ρ and high α are essential. We found that ρ and α are dependent on each other. The ρ value was ≈ 2× higher than the bulk material value, which is an excellent result for a thin film with the thickness of ≈ 80 nm.

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