Characteristics and Ferroelectric Properties of Pb(Zr, Ti)O_3 Capacitors with Pt/La_<0.5>Sr_<0.5>Co_<1.0>O_3 Top and La_<0.5>Sr_<0.5>Co_<1.0>O_3/SrTiO_3/Pt/SrTiO_3 Bottom Electrodes

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Sol-gel-derived Pb(Zr, Ti)O_3 films with thin, room temperature sputter-deposited and postannealed Pt/La_<0.5>Sr_<0.5>Co_<1.0>O_3 top and La_<0.5>Sr_<0.5>Co_<1.0>O_3/SrTiO_3/Pt/SrTiO_3 bottom electrodes were synthesized on SiO_2/Si(100) substrates, and the microstructures and ferroelectric properties were examined. Insertion of SrTiO_3 layers with optimum thicknesses in the bottom electrode improved surface roughness of the bottom electrode and the Pb(Zr, Ti)O_3 film, and strengthened the adhesion of the bottom electrode to the substrate. The stacking of La_<0.5>Sr_<0.5>Co_<1.0>O_3, SrTiO_3 and Pt layers in the bottom electrode yielded Pb(Zr, Ti)O_3 (40/60) films with flat surfaces; the fatigue tests at 3 V, 100kH indicated that switchable polarization was greater than 15 μC/cm^2, and no fatigue degradation was observed up to 10^<10> cycles. However, the PZT films with higher Ti concentration in the composition exhibited gradual decay in polariation from fatigue cycles of 10^6. The possible reason for the decay in polarization was discussed. The leakage current was of the order of 10^<-5> A/cm^2 at driving voltages of 2-3 V; considerable scattering among the leakage current data was observed.
社団法人応用物理学会の論文
1999-12-15