Pb过量对以Ti-Al为阻挡层的硅基铁电电容器极化翻转性能的影响

Effect of Lead Excess on Polarization Switching Properties of Si-based Ferroelectric Capacitor with Ti-Al Barrier Layer

以射频磁控溅射法生长的La0.5Sr0.5CoO3(LSCO)为电极,采用溶胶-凝胶法在以Ti-Al为导电阻挡层的Si基片上生长了用不同Pb过量前驱体溶液(溶胶)制备的LSCO/Pb(Zr0.4Ti0.6)O3(PZT)/LSCO电容器,以此构造了Pt/LSCO/PZT/LSCO/Ti-Al/Si异质结。Pb过量对LSCO/PZT/LSCO电容器极化翻转性能的影响表明:不同Pb过量溶胶对电容器的极化翻转性能影响很大,其中Pb过量15%的溶胶制备的样品在550℃常规退火1 h后相对具有较好的翻转性能。在5 V的外加电场下,LSCO/PZT/LSCO电容器的矫顽电压和剩余极化强度分别为1.25 V和24.6μC/cm2。疲劳和电阻率测试分析表明:在经过109翻转后,不同样品的抗疲劳性能均很好,而电阻率随前驱体溶液Pb过量的增加呈现下降的趋势。

Pt/La0.5Sr0.5CoO3 （ LSCO ）/Pb （ Zr0. 4 Ti0. 6 ） 03 （PZT）/LSCO/Ti-A1/Si heterostructure has been fabricated, in which the sputtered LSCO films were used as the electrodes of the LSCO/PZT/LSCO capacitor, PZT films were prepared by sol-gel technique using different excess lead, and using Ti-A1 as aconducting barrier layer. The effect of lead excess on the swithching properties of the LSCO/PZT/LSCO capacitor has been investigated. The results indicated that lead excess has great impact on the switching properties of the capacitors, and the stoichiometric Pb（ Zr0.4Ti0.6 ）03 film, annealed in a conventional annealing furnace at 550℃ for 1 h, could yield the best switching properties, which corresponds to 15%lead excess in the precursor. The coercive voltage and remnant polarization of the LSCO/PZT/LSCO capacitor were 1.25 V and 24.6μC/cm^2, respectively, measured at the voltage of 5 V. Moreover, it is found that the LSCO/PZT/LSCO capacitor is fatigue free up to 10^9 switching cycles ,and the resistivity ofthe capacitor decreases with the increase of lead excess of the precursor.