Effect of CaRuO₃ interlayer on the dielectric properties of Ba(Zr,Ti)O₃ thin films prepared by pulsed laser deposition

Abstract

Ba(Zr[sub 0.2]Ti[sub 0.8])O₃ (BZT) thin films on Pt(111)/Ti/SiO₂/Si(100) substrates without and with CaRuO₃ (CRO) buffer layer were fabricated at 650 °C in situ by pulsed laser deposition. The BZT thin films showed a dense morphology, many clusters are found on the surface images of BZT/Pt films, which are composed by nanosized grains of 25-35 nm; the average grain size of BZT/CRO films is about 80 nm, which lager than that of BZT/Pt thin film. The dielectric constants and dissipation factors of BZT/Pt and BZT/CRO thin films were 392 and 0.019 and 479 and 0.021 at 1 MHz, respectively. The dielectric constant of BZT/Pt and BZT/CRO thin films changes significantly with applied dc bias field and has high tunabilities and figures of merit of ~70% and 37 and 75% and 36, respectively, under an applied field of 400 kV/cm. The possible microstructural background responsible for the high dielectric constant and tunability was discussed.