Materials World Network: High Frequency Response of High-permittivity Thin Films

材料世界网：高介电常数薄膜的高频响应

• 批准号: 0602244
• 负责人: Susanne Stemmer
• 金额: $ 30.1万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0602244&HistoricalAwards=false
• 关键词: Materials; World; Network; Frequency; Response

The objective of the research is to gain an experimental and theoretical understanding of dielectric losses in ferroelectric thin films. The effort is motivated by microwave devices and circuits that make use of high-permittivity thin films and the large electric field tunability of the dielectric constant of ferroelectric thin films. In parallel with the progress in device technology, a number of scientific questions have emerged. In particular, the origins of high dielectric losses in thin films used for tunable devices are not understood. While it is known that thin films often accommodate a high density of defects and large stresses, experimental studies are needed that address the relationship between specific defects and the dielectric loss. Furthermore, only limited theoretical understanding exists with respect to the nature of the coupling of specific defects to the dielectric properties. Understanding the origins of thin film losses would not only enable new applications by improving device performance but also advance our understanding of the materials physics of dielectric thin films at high-frequencies and the relationship between dielectric response and materials defects. The research addresses these questions by complementary experimental and theoretical studies aimed at elucidating the relative contributions of defects, strain and intrinsic mechanisms to the dielectric loss of high-permittivity oxide thin films. The project is carried out in collaboration with Dr. Tagantsev of the cole Polytechnique Fdrale de Lausanne (EPFL) in Switzerland. Thin films of tunable dielectrics, such as (Ba,Sr)TiO3 and SrTiO3, will be synthesized and characterized at UCSB, and the results from dielectric loss measurements will be compared with the predictions of the models developed at EPFL. The theoretical effort will provide guidelines for the interpretation of the experimental results, which will be used to test the validity of the theoretical models and to motivate further developments. The collaborative program will involve graduate students at UCSB and at EPFL. The interdisciplinary collaboration between students in experimental and theoretical materials science will allow the students to bridge the gap between applied and fundamental materials research. Exchange visits and collaboration meetings will train students in international collaboration, thus fostering an understanding of cultural nuances and research environments in another country. This award is co-supported by the Europe and Eurasia Program of the Office of International Science and Engineering.

本研究的目的是获得铁电薄膜中介电损耗的实验和理论认识。微波器件和电路利用了高介电常数薄膜和铁电薄膜介电常数的大电场可调性。随着设备技术的进步，出现了许多科学问题。特别是，用于可调谐器件的薄膜中高介电损耗的起源尚不清楚。虽然已知薄膜通常可以容纳高密度的缺陷和大应力，但需要进行实验研究来解决特定缺陷和介电损耗之间的关系。此外，只有有限的理论认识存在关于特定缺陷的耦合性质的介电性能。了解薄膜损耗的来源不仅可以通过提高器件性能来实现新的应用，而且还可以促进我们对高频介质薄膜的材料物理以及介电响应与材料缺陷之间关系的理解。本研究通过互补的实验和理论研究来解决这些问题，旨在阐明缺陷、应变和内在机制对高介电常数氧化物薄膜介电损耗的相对贡献。该项目是与瑞士洛桑理工学院（EPFL）的Tagantsev博士合作进行的。可调谐介质薄膜，如（Ba,Sr）TiO3和SrTiO3，将在UCSB合成并表征，并且介质损耗测量结果将与EPFL开发的模型预测结果进行比较。理论上的努力将为解释实验结果提供指导，这将用于测试理论模型的有效性并激励进一步的发展。该合作项目将包括加州大学圣迭戈分校和EPFL的研究生。学生在实验和理论材料科学方面的跨学科合作将使学生在应用和基础材料研究之间架起桥梁。交流访问和合作会议将训练学生进行国际合作，从而促进对另一个国家文化差异和研究环境的理解。该奖项由国际科学与工程办公室的欧洲和欧亚项目共同支持。