The Influence of Silicon Content and Synthesis Atmosphere on the Electrical Properties and Chemical Composition of Ru–Si–O Nanocomposites

This paper presents the results of the preparation and electrical characterization of Ru–Si–O thin-film nanocomposites deposited by magnetron sputtering (pDC) with varying oxygen content ranging from 0% to 50%. Measurements were conducted over a wide frequency range of 50 Hz–5 MHz and temperatures of 20–373 K. Conductivity analysis revealed that DC conduction occurs at low frequencies (≤10³ Hz), while an increase in conductivity associated with electron tunneling mechanisms is observed at higher frequencies. The determined charge transport activation energies range from 3 × 10⁻⁴ eV for the oxygen-free sample to 6 × 10⁻² eV for the high-oxygen samples, indicating a significant effect of composition on the conduction mechanisms. In samples containing 30% and 50% oxygen, two characteristic frequency ranges for the activation of transport processes were observed (e.g., ~10²–10³ Hz and 10⁴–10⁶ Hz), suggesting the coexistence of multiple tunneling mechanisms. Phase angle analysis revealed a transition from values near –90° at 151 K to values near 0° at 333 K, characteristic of parallel RC systems. The minimum dielectric loss tangent occurs in the range of 10³–10⁵ Hz, corresponding to Maxwell–Wagner relaxation. The dispersion coefficient α reaches maximums in two frequency ranges, decreasing with increasing oxygen content. EDS analysis showed a decrease in Ru content from ~24.9 at.% (0% O₂) to ~0.7 at.% (50% O₂) and an increase in oxygen content to ~78 at.% at 10% O₂. The results confirm the transition from metallic conduction to tunneling and hopping mechanisms with increasing oxidation state of the structure.