Dislocation Nucleation and Patterning in Thin Layered Materials: Deformation and Fracture Mechanisms

技术：很明显，21世纪将见证技术的无与伦比的进步：信息技术、纳米技术、生物技术，仅举几例。许多这些新发展的一个共同特征是硬件的小型化。为了在许多新兴技术中继续小型化的趋势，需要利用越来越小长度尺度的材料的行为。这项研究项目旨在解决与薄层材料的变形和破坏有关的基本科学和技术问题，特别是受限的薄金属薄膜中的位错活动。在这项研究中，将开发能够加载小规模样品的实验技术。透射电子显微镜结合FIB试件的制作将用于确定约束金属薄层中的位错组态及其演化。通过测量界面断裂韧性来评价位错对界面粘结和界面裂纹扩展的影响。离散位错动力学模拟被用来确定界面失效的临界条件，包括临界位错模式和界面性质。非技术性：这项研究将显著增强对薄层材料系统中位错成核和图案化的基本知识，加深对位错活动对界面粘结和裂纹扩展的影响的理解，并有助于确定薄层材料中的主要失效机制。这些基本认识将对微电子和MEMS行业的产品设计和开发产生重大影响。该项目还包括一项全面的学者交流和教育计划。学者交流计划包括通过电话和互联网定期举行研究会议，以及国际和平机构与德国合作者在德国斯图加特的马克斯·普朗克研究所进行年度互访。此外，PI和德国研究人员将共同为参与该项目的美国和德国研究生提供建议，以便学生能够接触到美国和德国机构的研究活动。这样的国际交流活动服务于更广泛的目标，即培养和培养出不仅拥有扎实的材料科学和工程知识，而且具有丰富的国际经验的新一代工程专业学生。

TECHNICAL: It has become clear that the 21st century will witness unparalleled progress in technologies: information technology, nanotechnology, biotechnology, to name a few. A common feature of many of these new developments is the miniaturization of hardware. To continue the trend of miniaturization in many emerging technologies, the behavior of materials at an increasingly smaller length scale needs to be harnessed. This research project is to address the fundamental scientific and technical issues associated with deformation and failure of thin-layered materials, in particular the dislocation activities in confined, thin metal films. In this study, experimental techniques that enable loading of small-scale specimens will be developed. TEM combined with FIB specimen fabrication will be used to determine the dislocation configurations and their evolution in confined metal thin layers. The effects of dislocations on interface adhesion and interfacial crack propagation are evaluated by measuring interfacial fracture toughness. Discrete dislocation dynamics simulations are conducted to identify critical conditions, including critical dislocation patterns and interface properties, for interfacial failure. NON-TECHNICAL: This study will significantly enhance the fundamental knowledge on dislocation nucleation and patterning in thin-layered material systems, enhance the understanding of the effects of dislocation activities on interfacial adhesion and crack propagation, and help identify the dominant mechanisms of failure in thin-layered materials. Such fundamental understanding will have significant impact on product design and development in microelectronics and MEMS industry. The project also contains a comprehensive scholar exchange and educational plan. The scholar exchange plan includes regular research meetings by phone and via the Internet, and annual mutual visits between the PI and the German collaborator at the Max Planck Institute in Stuttgart, Germany. Furthermore, the PI and the German researcher will co-advise U.S. and German graduate students working on the project so that the students are exposed to research activities at both U.S. and German institutions. Such international exchange activities serve the broader objective of training and producing a new generation of engineering students with not only solid knowledge in materials science and engineering, but also extensive international experiences.