Houwman Evert P, Nguyen Minh D, Dekkers Matthijn, Rijnders Guus
Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500-AE Enschede, The Netherlands.
Inorganic Materials Science (IMS), MESA + Institute for Nanotechnology, University of Twente, PO Box 217, 7500-AE Enschede, The Netherlands; SolMateS BV, Drienerlolaan 5, Building 6, 7522-NB Enschede, The Netherlands; International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology, No. 1 Dai Co Viet Road, Hanoi, Vietnam.
Sci Technol Adv Mater. 2013 Jul 30;14(4):045006. doi: 10.1088/1468-6996/14/4/045006. eCollection 2013 Aug.
Piezoelectric thin films of PbZrTiO were grown on Si substrates in four different ways, resulting in different crystalline structures, as determined by x-ray analysis. The crystalline structures were different in the spread in tilt angle and the in-plane alignment of the crystal planes between different grains. It is found that the deviations of the ferroelectric polarization loop from that of the ideal rectangular loop (reduction of the remanent polarization with respect to the saturation polarization, dielectric constant of the film, slanting of the loop, coercive field value) all scale with the average tilt angle. A model is derived based on the assumption that the tilted grain boundaries between grains affect the film properties locally. This model describes the observed trends. The effective piezoelectric coefficient shows also a weak dependence on the average tilt angle for films grown in a single layer, whereas it is strongly reduced for the films deposited in multiple layers. The least affected properties are obtained for the most epitaxial films, i.e. grown on a SrTiO epitaxial seed layer, by pulsed laser deposition. These films are intrinsically stable and do not require poling to acquire these stable properties.
通过四种不同方式在硅衬底上生长锆钛酸铅压电薄膜，X射线分析表明其具有不同的晶体结构。不同晶粒间的晶体平面在倾斜角分布和面内排列方面的晶体结构有所不同。研究发现，铁电极化回线与理想矩形回线的偏差（剩余极化相对于饱和极化的降低、薄膜的介电常数、回线的倾斜、矫顽场值）均与平均倾斜角成比例。基于晶粒间倾斜的晶界会局部影响薄膜性能这一假设推导出一个模型。该模型描述了观察到的趋势。对于单层生长的薄膜，有效压电系数对平均倾斜角也有微弱依赖，而对于多层沉积的薄膜，有效压电系数则大幅降低。通过脉冲激光沉积在最外延的薄膜（即在钛酸锶外延籽晶层上生长的薄膜）中获得的性能受影响最小。这些薄膜本质上是稳定的，无需极化就能获得这些稳定性能。
