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

Auburn University, Auburn AL

Investigators

Abstract

Abstract 0528265 Microscale 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.