Deposition and characterization of BaZr_xTi_1-xO₃ ferroelectric thin films for microwave tunable applications

BaZr_xTi_1-xO₃ (BZT, x=0.20, 0.25, 0.30 and 0.35) ferroelectric thin films were deposited on Pt/Ti/SiO₂/Si and (100) LaAlO₃ substrates via a pulsed laser deposition (PLD). The deposited BZT thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical measurement. The BZT thin films were of single phase perovskite structure. The films deposited on the Pt/Ti/SiO₂/Si substrate were polycrystalline, with a zero field dielectric constant of 641, 507, 485 and 419, and a maximum dielectric tunability of 59%, 68%, 65% and 53%, for the BaZr_xTi_1-xO₃ films of x=0.20, 0.25, 0.30 and 0.35, respectively. The films deposited on the LaAlO₃ substrate were epitaxial. BaZr_0.25Ti_0.75O₃ thin film on LaAlO₃ possessed a zero field dielectric constant of 413, a dielectric loss of 0.01 and a maximum dielectric tunability of 18%.