Structural and electrical properties of (Zr,Ti)_0.85(Ca,Sr)_0.15O_1.85 thin films grown on Cu/Ti/SiO₂/Si substrate using RF magnetron sputtering

(Zr,Ti)_0.85(Ca,Sr)_0.15O_1.85 (ZTCS) films grown on Cu electrode at room temperature showed a crystalline cubic stabilized ZrO₂ structure when large sputtering powers (≥ 75 W) were used. The smoothest film, grown at sputtering power of 75 W, showed the lowest leakage current (4.0 × 10⁻⁶ A/cm² at 0.75 MV/cm) and highest breakdown voltage (2.7 MV/cm) among all the films prepared, indicating that surface roughness considerably influences the electrical properties of the ZTCS film. A dielectric constant (k) of 21.5 and a tan δ of 0.007 were obtained at 100 kHz, and a similar k of 19.4 with a high quality factor of 52 at 2.0 GHz. Moreover, a high capacitance density (78 nF/cm²) and a small TCC (256 ppm/^oC at 100 kHz) were obtained. Such a ZTCS film therefore satisfies the requirements of the International Technology Roadmap for Semiconductors for capacitors grown on organic substrates for 2016.