Effects of texture on the dielectric properties of Ba(Zr0.2Ti0.8)O3 thin films prepared by pulsed laser deposition

Ba(Zr0.2Ti0.8)O-3 (BZT) thin films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by a pulsed laser deposition process. The BZT thin films directly grown on annealed and un-annealed Pt/Ti/SiO2/Si substrates exhibited random and high (100) orientations, respectively. The dielectric constant of a 400-nm-thick BZT film with (100) orientation was 331, which was higher than that of a BZT film with random orientation (similar to 236). This result is attributed to the fact that the polar axis of the (100)-oriented films was more tilted away from the normal to the film surface than that of the randomly oriented films. Also, the tunabilities of BZT thin films with random and (100) orientations were similar to 50% and similar to 59% at an applied field of 400 kV/cm, respectively. Improved tunability has been attributed to the (100) texture of the film leading to an enhancement of the in-plane-oriented polar axis.