Polycrystalline thin platinum films with thicknesses ranging from tens to hundreds of nanometers are used in MEMS devices owing to their desirable chemical, electrical, and mechanical properties. In this work, we explore the effect of mechanical stress on the elementary plasticity mechanisms in Pt thin films using state-of-the-art nanomechanical testing and characterization methods. Sputter deposited and freestanding dogbone patterned (lithography and XeF2 under etched) Pt films on Si wafer, with a thickness of 250 nm are deformed under uniaxial tension using a UCLouvain Lab-on-Chip (LOC) testing platform. The rate-dependent behavior of the Pt films is also investigated using the LOC technique. Efforts have been made to adapt the LOC structures for nano-digital image correlation (nano-DIC) 1 and for in-situ nanoscale observations inside the transmission electron microscope (TEM) 2 in order to investigate the synergy/competition between the underlying intra- and inter-granular plasticity mechanisms. This experimental approach was used on films with different grain sizes in order to unravel the effect of grain size on the mechanisms under interest.
Neshani et al. (Wed,) studied this question.