Effects of Excess Pb and Substrate on Crystallization Processes of Amorphous Pb(Zr, Ti)O_3 Thin Films Prepared by RF Magnetron Sputtering

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Effects of excess Pb and substrate on the crystallization processes of amorphous lead-zirconate-titanate (a-PZT) thin films by post-annealing in oxygen ambient were investigated to lower the crystallization temperature of the films with a single perovskite phase. A-PZT films were prepared on Ir and Pt substrates with a 2-nm-thick Ti buffer layer on their surfaces, and on a SrRuO_3 substrate by cosputtering Pb(Zr_<0.5>Ti_<0.5>)O_3 and PbO targets. Analyses by in situ heating X-ray diffraction revealed that the crystallization processes strongly depend on the amount of excess Pb contained in the as-prepared a-PZT and substrates. By controlling the rf power supplied to the PbO target during the deposition, we obtained single perovskite phase PZT films at 480℃, 520℃ and 580℃ on SrRuO_3, Ir and Pt substrates, respectively. The crystallized PZT films exhibited excellent ferroelectric properties. For the 150-nm-thick PZT film, crystallized by rapid thermal annealing at 600℃ for 20 s, we obtained a coercive field of 40 kV/cm (0.6 V), a remanent polarization density of 15 μC/cm^2 and polarization switching endurance over 1×10^9 cycles with Ir top and bottom electrodes.
社団法人応用物理学会の論文
1997-09-30