Integrating Experiments and Simulation for Advancing the Fundamental Science of Thin Films and MEMS Materials

微规模技术是国家经济转型、军事实力以及公民福祉和生活质量的一支新兴力量。正在开发使用微型传感器和设备的新应用，这些传感器和设备能够加强和实现更有效率和效力的保健、环境监测、电信、飞行中的飞机状况监测、弹药制导等，其中包括用于监测公共健康威胁和医疗诊断的生物传感器、用于DNA表达的大规模平行反应堆阵列、用于可调电容器的高效和大Q因数机械开关、光子网络、数字控制无线电和无线通信。阻碍这些技术快速部署到市场上的一个主要问题是对其健壮性和可靠性的评估。最近，一些行业杂志和其他期刊强调了这些问题，它们普遍表示，由于对其微型部件的材料失效机制缺乏基本了解，阻碍了微型传感器和设备的商业化。在这个项目中，研究人员将重点了解薄膜材料的微结构及其演变如何控制使用它们的工程部件的性能和可靠性。使用标准的半导体微机械加工技术将制造出尺寸在典型微尺度组件数量级的拉伸试件。样品将由微型设备中常用的材料制成，即金、镍、铜、铝、铂和银。一种名为膜偏转实验的新技术将被用来使样品受到均匀的拉应力。这将与最先进的高分辨率场发射电子显微镜的表征相结合，包括电子背散射衍射，使直径小至50纳米的颗粒能够获得单独的晶体取向。最后，这些数据将与数值模拟相结合，以促进计算工具的开发，使工程师能够预测薄膜材料的变形和失效行为。通过这种方法，将生成一个基本模型，该模型将检验导致薄膜金属材料变形和失效的各种机制的贡献。该模型将使工程师能够现实地预测薄膜的行为，并促进利用这一知识提高可靠性和/或功能的设备设计。

Abstract 0528265Microscale technologies are an emerging force in the transformation of the nation's economy, its military prowess, and the well-being and quality of life of its citizens. Novel applications are under development that employ microscale sensors and devices that enhance and enable more efficient and effective health care, environmental monitoring, telecommunications, in-flight aircraft condition monitoring, munitions guidance, etc. These include biosensors for monitoring public health threats and medical diagnostics, massively parallel reactor arrays for DNA expression, highly efficient and large Q-factor mechanical switches for tunable capacitors, photonic networks, digitally controlled radio, and wireless communication. A major issue hindering these technologies from rapid deployment to the marketplace is the evaluation of their robustness and reliability. These issues have been recently highlighted by several trade magazines and other periodicals, which generally state that the commercialization of microscale sensors and devices is hindered by a lack of fundamental understanding of material failure mechanisms of their microsized components. In this project the investigator will focus on understanding how the microstructure of a thin film material and its evolution control the performance and reliability of engineering components that employ them. Tensile specimens with dimensions on the order of typical microscale components will be fabricated using standard semiconductor micromachining techniques. Specimens will be made of materials commonly used in microscale devices; namely, gold, nickel, copper, aluminum, platinum and silver. A new technique, called the membrane deflection experiment, will be employed to subject the specimens to uniform tensile stress. This will be combined with characterization by state-of-the-art high-resolution field emission electron microscopy, including electron backscattered diffraction that enables the individual crystal orientations of grains as small as 50 nm in diameter to be obtained. Finally, this data will be integrated with numerical simulations to facilitate the development of computational tools that enables engineers to predict the deformation and failure behavior of thin film materials.By this method a fundamental model will be generated that examines the contribution of various mechanisms responsible for deformation and failure of thin film metallic materials. The model will enable engineers to realistically predict how thin films behave as well as promote the design of devices that take advantage of this knowledge for enhanced reliability and/or functionality.