Pyrochlore structure and dielectric properties of bismuth zinc niobate thin films prepared by RF sputtering

Bi_1.5Zn_1.0Nb_1.5O₇ (BZN) thin films with thickness from 60 nm to 200 nm were prepared by radio-frequency magnetron sputtering and post-annealed from 550 °C to 650 °C. The x-ray diffraction results indicated that the BZN thin films possessed a cubic pyrochlore phase. The BZN thin films exhibited thickness-independent dielectric properties with dielectric constant of ~180 and low loss tangent less than 1% at 10 kHz as the film thickness decreased to 60 nm. The BZN thin films with thickness of 200 nm and post-annealed at 650 °C had a tunability of 32.7% at a DC bias field of 1.5 MV/cm. The results suggest that the BZN thin films have promising applications on the embedded capacitors, tunable devices and energy storage devices.