Structural and tunable characteristics of Ba(Zr_xTi_1-x)O₃ films prepared by RF-magnetron sputtering using a metal target

Ba(Zr_xTi_1-x)O₃ (BZT) thin films with different Zr contents were deposited on (100)MgO and (100)Pt/(100)MgO substrates by RF-magnetron sputtering using metal targets. The BZT thin films epitaxially grew on MgO substrates with only a (001)/(100) orientation and had a single perovskite phase. In all cases, Ba/Ti ratio was stoichiometric and the BZT films possessed a dense microstructure. The grain size decreased with increasing Zr content. At room temperature, a dielectric constant as a function of the DC bais (tunability) of nearly 30% was achieved at 1 MHz; meanwhile, a relatively low dielectric loss was obtained. Moreover, after a post-annealing process, the tunability was increased significantly. These results indicate that we succeeded in depositing high-quality, and potential tunable ferroelectrics.