Mechanical deflection of cantilever microbeams: A new technique for testing the mechanical properties of thin films

Abstract

The mechanical deflection of cantilever microbeams is presented as a new technique for testing the mechanical properties of thin films. Single-layer microbeams of Au and SiO2have been fabricated using conventional silicon micromachining techniques. Typical thickness, width, and length dimensions of the beams are 1.0,20, and 30 μm, respectively. The beams are mechanically deflected by a Nanoindenter, a submicron indentation instrument that continuously monitors load and deflection. Using simple beam theory and the load-deflection data, the Young's moduli and the yield strengths of thin-film materials that comprise the beams are determined. The measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.