Novel Thin-Film Piezoelectric Materials for Ultrasound Applications

用于超声波应用的新型薄膜压电材料

• 批准号: 512808298
• 负责人: Professor Dr.-Ing. Gerhard Fischerauer
• 金额: --
• 依托单位: Leibniz-Institut für Kristallzüchtung (IKZ)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/512808298?language=en
• 关键词: Novel; Thin; Film; Piezoelectric; Materials

Our project explores a novel approach for designing high frequency planar microacoustic converters. Such devices are currently used for signal processing in mobile communication systems or as microacoustic sensors. It appears as if the performance limits of common piezoelectric single crystals (SiO2, LiNbO3, LiTaO3, AlN, …) have been reached. Our project employs a radically new approach to enhance the performance of the current microacoustic components. A key element is a functional thin film made from a novel piezoelectric material which is used to convert high frequency electrical into acoustic signals. Our innovation consists in controlling the functional material properties through epitaxial growth in order to optimize these properties with respect to a specificapplication. This is achieved on the one hand by intentionally straining the crystal lattice in a controlled way and, on the other hand, by purposefully introducing defects during film growth. Our thin films are fabricated from potassium-sodium-niobate (K_xNa_{1-x}NbO_3), which allows for piezoelectric ultrasound conversion. The electromechanical coefficients are comparable to lead-based piezoelectric compounds. However, there are no concerns about sustainability when using K_xNa_{1-x}NbO_3. The extremely thin film thickness of less than 100 nm is an essential novelty in comparison with current layered ultrasound converters. In particular, this enables tailoring of functional properties over a large range via strain- and defect engineering. Thus, structural material properties provide a new degree of freedom for the development of next generation ultrasound components. This project builds on the expertise of the collaborators for thin film growth of piezoelectric K_xNa_{1-x}NbO_3, its structural and functional characterization and for technology development for microacoustic components. By combining fundamental and applied material science with system design engineering we are able to explore the potential of this novel material in conjunction with innovative design strategies. However, development of specific devices is not a project goal. The successful execution of the project consists rather in the validation of the advantages of the novel material system at high operation frequencies (> 5 GHz) in comparison with known single-crystal substrates.

本课题探索一种设计高频平面微声转换器的新方法。这种装置目前用于移动通信系统中的信号处理或作为微声传感器。普通压电单晶（SiO2, LiNbO3, LiTaO3, AlN，…）的性能似乎已经达到极限。我们的项目采用了一种全新的方法来提高当前微声元件的性能。一个关键的元素是由一种新型压电材料制成的功能薄膜，该薄膜用于将高频电信号转换为声信号。我们的创新在于通过外延生长来控制功能材料的性能，以便针对特定应用优化这些性能。这一方面是通过以一种可控的方式有意地使晶格紧张，另一方面是通过在薄膜生长过程中有意地引入缺陷来实现的。我们的薄膜是由铌酸钾钠（K_xNa_{1-x}NbO_3）制成的，它允许压电超声转换。机电系数与铅基压电化合物相当。然而，当使用K_xNa_{1-x}NbO_3时，不存在可持续性问题。与现有的层状超声转换器相比，小于100纳米的极薄薄膜厚度是必不可少的新颖之处。特别是，这使得通过应变和缺陷工程在大范围内裁剪功能特性成为可能。因此，结构材料性能为下一代超声元件的开发提供了新的自由度。该项目建立在合作者对压电K_xNa_{1-x}NbO_3薄膜生长，结构和功能表征以及微声元件技术开发的专业知识的基础上。通过将基础和应用材料科学与系统设计工程相结合，我们能够探索这种新型材料与创新设计策略相结合的潜力。然而，开发特定的设备并不是项目的目标。该项目的成功实施在于验证了新材料系统在高工作频率（> - 5 GHz）下与已知单晶衬底相比的优势。