溶胶凝胶反提拉法制备PZT铁电薄膜及La3+, Ca2+离子混合掺杂对薄膜结构和性能的影响

采用醋酸铅、硝酸锆、钛酸丁酯制备的独立前驱单体，通过溶胶-凝胶反提拉涂膜技术在基片Pt／Ti／SiO2／Si上制备了锆钛酸铅(lead zlrconate titanate，PZT)铁电薄膜。反提拉涂膜技术是通过逆向思维而提出的薄膜制备新方法，该技术避免了浸渍提拉涂膜存在的机械传动装置较难操作和控制的问题，且能够一次性在多个异形器件上同时大面积涂膜。分析了不同金属离子掺杂，特别是高、低价离子混合掺杂对薄膜微结构和性能的影响，发现：同时掺杂La^3 ，Ca^2 离子比单独掺杂La^3 离子薄膜的剩余极化强度Pr大，且漏电电流明显减小，另外金属离子掺杂有利于降低薄膜晶化温度和增大晶粒尺寸。

PZT FILMS PREPARED BY REVERSED-DIP-COATING OF SOL-GEL AND EFFECTS OF La3+,Ca2+ DOPING ON ITS STRUCTURE AND ELECTRICAL PROPERTIES

Lead zirconate titanate (PZT) films on Pt/Ti/SiO_2/Si substrate were prepared by the solgel method of reverse-dip-coating with separated precursor-monomers. The preposed reverse-dip-coating is a new coating method that is reversing to the traditional dip-coating process. The reverse-dip-coating method overcomes disadvantages of spin coating and conventional dip-coating. It avoids the difficult problems of operation and control in the mechanical transmission device and can fabricate homogenous films over large areas or on many irregular shaped devices in one coating process. The effects of different doping with metallic ions on the structure and electrical properties of PZT thin films were investigated, especially doping with metallic ions of high and low chemical valences together. It is found that the films doped with La~(3+),Ca~(2+) presence higher remnant polarization P_r and lower leakage current, compared with the films doped with only La~(3+) and undoped films. The doping of metallic ions is favorable for decreasing crystallization temperatures and increasing grain sizes.