Low resistivity Ru1-xTixO2 thin films deposited by hybrid high-power impulse magnetron sputtering and direct current magnetron sputtering technique

Highlights: • Low resistivity Ru_1-xTi_xO₂ thin films by reactive hybrid HiPIMS/DCMS technique • Impact of structure and morphology on optical and electrical properties • Ti substitute Ru and shift the material from conductor to semiconductor -- Abstract: The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru_1-xTi_xO₂ thin films. Rutile single-phase Ru_1-xTi_xO₂ thin films have been deposited by reactive hybrid High-power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) at a substrate temperature of 250 °C. The HiPIMS source was applied to the Ru target while the DCMS source was connected to the Ti target in order to vary the Ti content in the films. The films are well crystallized and compact with randomly orientated nanocrystallites. The optical properties have been investigated by ellipsometric measurements in the optical energy range from 1.3 eV to 3.3 eV, while the electrical resistivity has been measured in the Van der Paw configuration at room temperature. The electrical resistivity increases gradually from 70 μΩcm for pure RuO₂ to about 243 μΩcm for Ru_1-xTi_xO₂ films with x = 0.13. The optical properties are correlated with the Ti doping. The refractive index n changes from a strong dispersion relationship to a moderate one with increasing Ti content.