Basic Studies of the Effects of Microfabrication, Environment, and Cyclic-Loading on the Long-Term Durability of Thin-Film Microstructures

Komvopoulos材料和结构的长期耐久性研究将研究设计和微加工对多晶硅微结构的微机械性能的影响。为了更好地了解循环应力（或应变）幅度和疲劳寿命之间的关系，多晶硅加工在不同的条件下，暴露在不同的环境中，一个创新的实验方案的基础上表面微加工技术将被使用。最终的目标是研究制造工艺参数（掺杂，蚀刻和退火），试样尺寸，微结构特性（晶粒尺寸），类型和幅度的负载，和环境条件对多晶硅薄膜微结构的机械性能和耐久性的影响。 设计考虑因素，工艺参数，和随后的耐久性的微观结构，以抵抗裂纹萌生之间的关系将进行调查。表征技术将包括成像和表面力微探针实验，一个新的真空探针站专门设计用于模拟典型的微机械操作条件，分析疲劳行为和裂纹萌生。本计画将提供一个绝佳的机会，培养研究生在高耐久性设计的微机电系统装置。这项工作将推进在微观尺度上的材料退化的知识基础。

DMI-9872324 Komvopoulos This research in Long Term Durability of Materials and Structures will study the effects of design and micro-fabrication on the micromechanical properties of polysilicon microstructures. In order to develop a better understanding of the relationship between cyclic stress (or strain) amplitude and fatigue life for polysilicon processed under different conditions and exposed to different environments, an innovative experimental scheme based upon surface micromachining technology will be used. The ultimate objective is to investigate the effects of fabrication process parameters (doping, etching, and annealing), specimen size, microstructure characteristics (grain size), type and amplitude of loading, and environmental conditions on the mechanical behavior and endurance of polysilicon thin-film microstructures. The relationship between design considerations, processing parameters, and subsequent durability of the resulting microstructures to resist crack initiation will be investigated. Characterization techniques will include imaging and surface force microprobe experimentation, with a novel vacuum probe station specifically designed to simulate typical micromachine operating conditions, to analyze the fatigue behavior and crack initiation. This project will provide an excellent opportunity for training graduate students in high endurance design of microeletromechanical systems devices. The knowledge base for material deterioration at the microscale will be advanced with this work.