Nanoindentation of Microspring Thin Films

ABSTRACTPorous thin films with helical microstructures were fabricated with the Glancing Angle Deposition technique. These films consisted of arrays of “microsprings” whose geometries could be engineered with nanometer scale control. Some of the mechanical properties of these helically structured films were studied with a nanoindentation technique. Several microscopic “springbed” films were tested over a range of forces using a spherical indenter tip. The geometries of the microsprings were varied, and a number of different materials were used to fabricate these films, which were typically a few micrometers thick. Slanted post arrays, resembling micro-cantilevers, were also subjected to nanoindentation tests. Results of initial experiments, theory, and simulations show that these microstructures behave in a manner analogous to macroscopic springs and cantilevers, and may offer some insight into how materials behave at the microscale.