Internal oxidation of laminated ternary Ru–Ta–Zr coatings

Internally Oxidized Ru–Zr Multilayer Coatings

“…The O and Zr species were identified as O 2− and Zr 4+ , whereas Ru was identified as Ru 0 except for the spectra near the surface region (depth < 13 nm), where the Ru x+ and Ru 4+ signals were split. The binding energy value of Ru 0 3d 5/2 (279.96 ± 0.08 eV) was consistent with that of other coatings (279.69-280.16 eV) reported in the literature [13,16,17,27], whereas the binding energies of Ru x+ and Ru 4+ 3d 5/2 were 280.45 ± 0.11 and 282.57 ± 0.15 eV, respectively. Previous studies reported 281.4-282.2 eV [26,[28][29][30] for the binding energy of Ru 4+ 3d 5/2 .…”

“…An oxidized laminated structure formed because of the inward diffusion of oxygen during the annealing process; this structure comprised alternating oxygen-rich and oxygen-deficient sublayers stacked adjacent to the surface. The inward diffusion of oxygen at 600 • C was dominated by lattice diffusion in the active element-enriched regions [13,16,17]. Because the elements were stacked on the substrate with an alternating gradient concentration, the O atoms could easily diffuse through the paths in the transverse direction, thereby forming oxide sublayers.…”

“…30 Ru 0.70 coating exhibited a relatively high value of 18.4 GPa. The widths of the oxide sublayers were restricted by the Ru-dominant sublayers [16,17]; therefore, the internally oxidized coatings can be categorized as nonisostructural oxide/metal multilayers [1]. The substrate holder rotation speed in sputtering affects the stacking period of the laminated structure [14]; therefore, assessing the effect of the stacking period on the mechanical properties of the internally oxidized Ru-Zr coatings is imperative.…”