Mechanical properties of MEMS materials

MEMS use materials such as polysilicon, which have been extensively characterized as to their electrical properties but not for their mechanical properties. The properties of aluminum are of course well known, but not for freestanding thin films. In a very real sense, the materials used in MEMS are new materials and require novel test methods. One cannot simply cut out a specimen and place it in a test machine; one must design the specimen to be attached to the substrate at some point yet free to deform. Measuring the small forces and displacements is a challenge, and it is particularly difficult to measure strain at the micro scale.