Composition dependence of dielectric properties of (Ta2O5)1−x(TiO2)x polycrystalline ceramics

(Ta2O5)1−x(TiO2)x has been the most promising capacitor material to be used in the near future dynamic random access memories (DRAMs), because of its high dielectric constant, thermal and chemical stability, and good step coverage. To explore the composition dependence of dielectric properties, (Ta2O5)1−x(TiO2)x ceramics for 0.00≤x≤0.12 with an interval of 0.01 were prepared and studied utilizing an HP4192A impedance analyzer, Raman scattering and X-ray diffraction (XRD) techniques. The dielectric properties of (Ta2O5)1−x(TiO2)x ceramics are greatly dependent on the compositions in this range. The greatest enhancement of dielectric constant occurs when TiO2 substitution reaches 8%. The Raman scattering and XRD studies indicate that there is some kind of phase structure appearing when a small quantity of TiO2 is doped into Ta2O5. But in vicinity of x=0.08, the phase structure of these compositions is same as that of pure Ta2O5, which is different from the previous studies.