Dielectric properties of (Ba,Ca)(Zr,Ti)O3/CaRuO3 heterostructure thin films prepared by pulsed laser deposition

(Ba0.90Ca0.10)(Zr0.25Ti0.75)O3 (BCZT) thin films were grown on Pt/Ti/SiO2/Si substrates without and with a CaRuO3 (CRO) buffer layer using pulsed laser deposition (PLD). The structure and surface morphology of the films have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). At room temperature and 1 MHz, the dependence of dielectric constant and tunability of the films with electric field were investigated; the dielectric constant and tunability are 725 and 47.0%, 877 and 50.4%, respectively, for the BCZT film on Pt/Ti/SiO2/Si substrates without and with the CRO buffer layer at 400 kV/cm. The tunability of the BCZT/CRO heterostructure thin films on Pt/Ti/SiO2/Si substrates was higher than that of the BCZT thin films on Pt/Ti/SiO2/Si substrates. The high constant likely results from the oxide electrode (CRO).