Characterization of dielectric and acoustic properties of CSD PZT thin films at high frequencies

In this study, the microwave dielectric and the acoustic properties of Pb(Zrx,Ti1-x)O3 (PZT) thin films deposited using chemical solution deposition (CSD) were investigated using the same measurement setup. High dielectric constants in the range of ~280–540 and loss tangents less than 0.1 at 4 GHz were measured, where the value depends on the thickness of the PZT film. The voltage tunability of the 340 nm and 440 nm thick PZT thin films was ~34% and 5% for the 140 nm thick PZT film at 120 kV/cm and 4 GHz. The acoustic parameters of the PZT thin films under DC bias voltages were determined using a one-dimensional acoustic wave resonator model. For the PZT films of thicknesses 340 nm and 440 nm, the acoustic resonance frequency shift was about 15 MHz and the electromechanical coupling coefficient was ~10% at an electric field of 160 kV/cm. The large dielectric constant and high tunability suggest that the characterized PZT thin films may be suitable for radio frequency (RF) applications such as high-density RF MIM capacitors and other tunable devices.