Paper MN-MoA3
In Situ SEM Micro Tension Tests on Nanoscale Single Crystal Metals and Nanocrystalline Metals

Monday, October 29, 2012, 2:40 pm, Room 10

We developed a microscale uniaxial tension test MEMS device for in-situ SEM experimentation, with potential use for in-situ TEM experiments as well. We have characterized batch compatible integrated ultra-thin nanocrystalline gold nanoscale samples (~40nm thick), as well as externally integrated single crystal gold, and single crystal gold-silver thin-film nanoscale samples (~100nm thick) for their mechanical properties in-situ SEM.

The MEMS device is composed of an electrostatic comb-actuator, and two displacement sensors, with the purpose to mechanically characterize nanoscale samples that are located between the two displacement sensors. Sub-pixel resolution Digital Image Correlation (DIC) on SEM micrographs is used as displacement tracking technique in order to quantitatively characterize the displacement fields of the displacement sensors so as to obtain the force-elongation (hence, stress-strain) behavior of the tested samples. From the stress-strain behavior of the tested nanoscale specimens, we experimentally obtained fundamental material properties such as Young’s modulus, and critical resolved shear stress for single crystal materials, and Young’s modulus for nanocrystalline ultra-thin gold samples.

The method we apply in this study is the first in its field with the capability to integrate such small samples to MEMS with monolithic microfabrication. Although we worked with ultra-thin film gold, and thin-film gold and gold-silver alloy, the method can be adapted to other materials of interest, such as metals, carbon nanotubes, and graphene.

The results of the experiments are of interest to microelectronics industry, and materials research community.