高压电性能锆钛酸钡钙薄膜的取向优化研究

Extremely high piezoelectric properties were obtained at the polymorphic phase transition (PPT) of the Ba1-yCayZrxTi1-xO3 (BCZT) materials, however, the piezoelectric properties of BCZT thin films were not as good as that of BCZT bulk materials. It was found that oriented and/or epitaxial structure could improve the piezoelectric properties of thin films. Moreover, it was close to application for the study of relationship of orientation and piezoelectric properties at low temperature that suit to semiconductor technology. In this study, the oriented BCZT thin films with high piezoelectric properties will be prepared by semiconductor technology. The orientation of BCZT thin film could be controled by the optimized component, buffer layers and experimental procedure. The effect on orientation growth and interface by buffer layer will be studied. The relationship of orientation, microstructure and piezoelectric properties will be explored, meantime, the proposals which enhance the piezoelectric properties will be optimized. The study could provide theory and techniques for the application in micro electro mechanical systems and information field.

Ba1-yCayZrxTi1-xO3 (BCZT)材料在多晶型相变(PPT)处具有极高压电性能，然而，当前BCZT薄膜材料的压电性能远不及其块体材料。研究表明，薄膜取向或外延生长是改善其压电性能的有效途径之一。另外，在硅基电路能承受较低的结晶温度下，研究薄膜取向类型与压电性能关系具有重要的实际应用价值。本项目拟采用基于硅工艺的薄膜制备方法，通过材料组成选择、缓冲层优化和制备工艺改进等，调控BCZT薄膜的取向生长，进而在较低结晶温度下获得取向生长的高压电性能薄膜材料。在此基础上，研究缓冲层对薄膜取向及界面的影响规律；探索薄膜的取向类型、微观结构与压电性能之间的关系，揭示其产生高压电性能的机理；优化出提高无铅薄膜压电性能的方案，为其在微机电系统和信息领域中的应用奠定理论与技术基础。

高灵敏度、大应变的压电材料在微执行器和传感器方面具有独特的应用优势，成为人们探索与研究的重要方向之一。BCZT材料在多晶型相变处具有优异的电学性能。取向或外延生长是提高其压电性能的有效途径之一。本项目通过材料组成选择、缓冲层优化和制备工艺改进等，调控薄膜的取向生长；探索了薄膜的取向类型、微观结构与压电性能之间的关系，揭示了其产生高压电性能的机理；优化出提高无铅薄膜压电性能和多功能性的方案。.研究表明，通过精细调控薄膜组分在无铅压电薄膜的准同型相界附近可以获得较高的压电响应（局部有效压电系数可达120pm/V）；籽晶层的引入可以极大的降低表面粗糙度，提高薄膜结构和性能，使其在多功能集成器件中得到实际应用；在（100），（110），（111）方向外延生长的薄膜电学性能随晶体学取向呈现各向异性，电学性能得到进一步提高有效压电系数最高为210pm/v，介电常数1170可调率68% ，剩余极化强度18 μC/cm2。通过引入稀土离子在BCZT压电材料体系中诱发荧光效应，实现压电材料多功能化，通过外电场可以有效调控材料的压电性能和发光性能，极化电场20kV/cm时，压电常数达450 pC/N，光致发光猝灭70%，这对研发新型光电器件起到一定的推动作用。