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 conditio ns of the thin films with a single-phase perovskite were systematically inv estigated by varying the processing parameters. It was found that the PZT t hin films pyrolyzed at 350-500 degreesC and then fired at 700 and 750 degre esC consisted of a single-phase perovskite, whereas a microcrystalline pyro chlore phase remained in the perovskite matrix when the thin films were fir ed at 600 and 650 degreesC. No appreciable improvement in the dielectric an d the ferroelectric properties was found by increasing firing temperature f rom 700 to 750 degreesC, but the leakage current density of the thin film f ired 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 de termined to be 700 degreesC, single-phase perovskite being obtained with op timum dielectric and ferroelectric properties as well as a low leakage curr ent. The Pr are around 38-46, 30-40 and 25-30 muC/cm(2) and the coercive fi eld 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 control led by a pyrolysis process rather than by the firing temperature and the co mposition of the precursor solution. The PZT pyrolyzed at 400 degreesC tend s to take [100] orientation, whereas the counterpart pyrolyzed at 350, 450 and 500 degreesC have a strong [111] dominating orientation.