EFFECT OF PRECURSORS AND STACKING STRUCTURES ON CRYSTALLIZATION OF MULTI-LAYERED LEAD ZIRCONATE TITANATE THIN FILMS BY SOL-GEL METHOD

摘要

Ferroelectric lead zirconate titanate, Pb(Zr_xTi_(1-x))O_3 (hereafter abbreviated as PZT), thin films were prepared by annealing precursor films of multilayered structures composed of alternating layers of PZT and lead titanate (hereafter abbreviated as PT). This method (which we refer to as multi-seeding) was used in order to lower the processing temperature of PZT. The precursor films were prepared from alkoxide precursor solutions. Effects of zirconium to titanium ratios and stacking structures of the multi-layered precursor films on crystallization behavior were studied to improve the electrical properties of the resultant PZT thin films. Layers of PT were inserted between every PZT layer in order to seed the crystallization of the desired perovskite phase. PT has previously been shown to crystallize with a pure perovskite structure at temperatures as low as 450 deg C. Precursor layers of PZT with different compositions, ranging from x=1 to x=0.53 were prepared. In this process, the compositions of the PZT precursors and/or the stacking structure, as well as the heating schedule, had a large effect on the crystallization behavior. Nucleation control of the PT seeding layer by changing the heating schedules played an important role in preparing perovskite PZT thin films at low temperatures. Dielectric properties of the resultant films depended on the compositions and annealing temperatures. It was demonstrated that the composition of the resultant PZT film was controllable in the multi-seeding process, and that dielectric properties of the resultant films were improved.