TUNABLE DIELECTRIC BEHAVIORS OF BARIUM ZIRCONATE TITANATE THIN FILMS

ABSTRACT The dielectric tunability of Ba(ZrxTi1−x)O3 (x = 0.20, 0.25, 0.30 and 0.35, respectively) thin films epitaxially grown on MgO (001) single crystal substrates were investigated. The BZT thin films were deposited by means of pulsed laser ablation followed by annealing at 1100°C. X-ray diffraction revealed that the thin films were all well crystallized and epitaxially aligned on the substrate. The in-plane dielectric properties of the BZT thin films were characterized on a network analyzer. It is found that all the films have moderate dielectric constants and good tunability. Comparatively, however, Ba(Zr0.30Ti0.70)O3 seems to be the most suitable candidate for making prototype microwave devices due to its largest tunability among all the samples. The typical in-plane dielectric properties of Ba(Zr0.30Ti0.70)O3 thin film are: dielectric constant = 240 (at 10 MHz), tunability = 26% (at 1 GHz and under dc bias of 13 MV/m).