Determination of Strain Fields at the Nanometer Scale with Applications to MEMS Design and Micromechanics

摘要

This project focused on the determination of mechanical properties of thin films manufactured by polycrystalline silicon using the surface micromachining method. In addition to the measurement of mechanical properties by using an Atomic Force Microscope (AFM) or a Scanning Tunneling Microscope (STM) with the aid of the Digital Image Correlation Method (DIC), several other aspects of fracture behavior were addressed, including the effects of surface roughness and of notches to the fracture of the specimen in conjunction with grain size. This report summarizes the progress made on this program from August 1998 to September 1999. Several aspects of the material behavior and characteristics were addressed, such as material constants, surface condition, and the material behavior after long treatment by an etchant. The year also resulted in improvements to the loading device of the test setup and work on potential fracture mechanics specimen geometries. In addition, modifications were made to the STM to improve its performance. At the same time, an error analysis on the DIC was conducted, and a new approach to STM/DIC error analysis was investigated. (9 figures).