Acquisition of Nanomechanical Instrumentation

该赠款为获得纳米压痕系统提供支持，该系统由纳米硬度计（NHT）和原子力显微镜组成。许多从事材料表征和纳米机械应力分析的不同研究小组将受益于NHT的获得。纳米压痕系统将致力于在微米和纳米尺度上研究MEMS材料的微观力学行为。它允许各种各样的测试，包括亚微米尺寸的硬度测试、微划痕测试、循环压痕期间的接触疲劳和恒载荷蠕变测试。该仪器将用于以下几个研究项目：(1)测量MEMS材料的微机械性能作为微加工工艺和温度的函数，为建模和理解MEMS微元件的加工-性能关系提供微机械性能；(2)研究与两个硅表面循环接触或累积损伤相关的硅片接触疲劳和表面裂纹萌生，以确定导致MEMS器件接触损伤和失效的关键变量；(3)研究MEMS微元件两个表面之间由于界面力(如毛细管力、范德华力、在微观尺度上了解控制固体接触面之间键合的主要机制。这种纳米硬度计是肯塔基大学的第一台。这将对MEMS结构的微观力学以及MEMS材料和纳米材料的表征研究产生重大影响。例如，由于高表面积体积比，表面和界面应力在决定MEMS微元件的变形特性方面起着重要作用。通过纳米压痕测试确定的微机械性能将考虑表面效应，如表面应力。长期研究目标是发展对与微机电系统相关的先进材料的材料特性（包括弹性，塑性，附着力和断裂）的理解。

The grant provides support for the acquisition of a nano-indentation system, consisting of a nano-hardness tester (NHT) and an atomic force microscope. Many diverse research groups that are involved in the characterization of materials and in nanomechanical stress analysis will benefit from the acquisition of the NHT. The nano-indentation system will be devoted to the study of micromechanical behavior of MEMS materials on both the micrometer and the nanometer scale. It allows a wide variety of tests, including submicron-sized hardness tests, micro-scratch tests, contact fatigue during cyclic indentation, and constant load creep tests. The instrument will be used in several research projects: (1) the measurement of micromechanical properties of MEMS materials as a function of microfabrication processes and temperature to provide both the micromechanical properties for modeling and the understanding of processing-properties relationships of MEMS microcomponents, (2) the investigation of the contact fatigue of silicon wafers and surface crack initiation associated with cyclic contact between two silicon surfaces or accumulated damage to identify the key variables responsible for contact damage and failure in MEMS devices, and (3) the study of adhesion phenomena between two surfaces of MEMS microcomponents due to interfacial forces, such as capillary, van der Waals, and electrostatic forces to understand the dominant mechanisms controlling the bonding between solid contact surfaces on the microscale. %%%This nano-hardness tester is the first of its kind at the University of Kentucky. It will have a large impact on research dealing with micromechanics of MEMS structure and characterization of MEMS materials and nanomaterials. For example, it is clear that surface and interface stresses play an important role in determining the deformation characteristics of MEMS microcomponents due to the high surface area to volume ratio. The micromechanical properties determined via nanoindentation tests will allow for consideration of surface effects, such as surface stresses. The long-term research goal is to develop an understanding of the material properties (including elasticity, plasticity, adhesion, and fracture) of advanced materials relevant to micro-electromechanical systems.