Preparation and ferroelectric properties of PZT thin films using a chemical solution deposition process

Lead zirconate titanate (PZT) thin films with various compositions near the morphotropic phase boundary were prepared on Pt(111)/Ti/SiO2/Si substrates using a chemical solution deposition (CSD) process. The formation conditions of the thin films with a single-phase perovskite were systematically investigated by varying the processing parameters. It was found that the PZT thin films pyrolyzed at 350-500 degreesC and then fired at 700 and 750 degreesC consisted of a single-phase perovskite, whereas a microcrystalline pyrochlore phase remained in the perovskite matrix when the thin films were fired at 600 and 650 degreesC. No appreciable improvement in the dielectric and the ferroelectric properties was found by increasing firing temperature from 700 to 750 degreesC, but the leakage current density of the thin film fired at 750 degreesC is about three orders of magnitude higher than that of the thin film fired at 700 degreesC. The optimal firing temperature was determined to be 700 degreesC, single-phase perovskite being obtained with optimum dielectric and ferroelectric properties as well as a low leakage current. The Pr are around 38-46, 30-40 and 25-30 muC/cm(2) and the coercive field to 141-192, 119-136 and 80-95 kV/cm, respectively, for the Pb(ZrxTi1-x)O-3 (x=0.45, 0.53 and 0.6) pyrolyzed at 350-500 degreesC for 3 min and then fired at 700 degreesC. The orientation of the PZT thin film can be controlled by a pyrolysis process rather than by the firing temperature and the composition of the precursor solution. The PZT pyrolyzed at 400 degreesC tends to take [100] orientation, whereas the counterpart pyrolyzed at 350, 450 and 500 degreesC have a strong [111] dominating orientation.