Preparation of La-modified lead titanate film capacitors and influence of SrRuO3 electrodes on the electrical properties

SrRuO3 electrodes are expected to dramatically improve the electrical prope rties of PbTiO3 based ferroelectric film capacitors. Because of the good fe rroelectricity and pyroelectricity of La-modified lead titanate (PLT), PLT film capacitors with SrRuO3, and Pt electrodes were prepared. The PLT and S rRuO3 films were prepared by YAG(YAG) laser ablation. YAG laser ablation ha s advantages over the conventional excimer laser ablation in running cost a nd safely. The dependence of ablation conditions on the composition and str ucture of PLT films obtained by the YAG laser ablation was revealed. The el ectrical properties of the capacitor with SrRuO3 were compared with Pt. As a result, the low leakage current was successfully obtained from the capaci tors with SrRuO3 electrodes. Furthermore, little polarization fatigue occur red in a SrRuO3/PLT/SrRuO3 capacitor after 10(10) switching cycles. The ele ctrical properties of the capacitors with Pt and SrRuO3 top electrodes are discussed. The dielectric property, D-E hysteresis curves and C-V character istics were not affected by the top electrode material. However, it was fou nd that the leakage current was significantly influenced by it. The results can be explained on the basis of the Schottky barrier that formed at the i nterface between the top electrode and the PLT layer. Based on these result s, the conduction mechanism in PLT thin-film capacitors was investigated.