Structural and Thermal Stability of B4C/Ru Multilayers with Carbon Barrier Layers

Abstract

The chemical interaction between B 4 C and Ru layers in multilayer structures depending on the thickness ratio (Γ) was carried out using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and X-ray reflectometry (XRR). The results showed significant interaction of materials inside multilayer structures with the formation of ruthenium borides, with an increase in the B 4 C layer thickness (a decrease in the Γ parameter) leading to the formation of ruthenium borides of different stoichiometry. The introduction of a carbon barrier layer at the Ru-on-B 4 C interface resulted in significant suppression of ruthenium boride formation. The thermal stability of the B 4 C/Ru system was also studied upon annealing at 400 ℃ for 1 hour before and after the introduction of the carbon barrier layer. It was shown that the introduction of a carbon barrier layer at the Ru-on-B 4 C interface increases the thermal stability of the system, which makes this system more suitable for use in optical systems exposed to long-term radiation. The obtained results are important for the development of highly efficient multilayer mirrors used in EUV lithography and X-ray optics.