Design and Development of Internal Friction and Energy Loss Measurement on Nanocrystalline Aluminum Thin Films
A technique developed for studying the internal friction and energy loss of nano-scale thin metal films on substrate is presented. The test microstructure was designed on the triangular cantilever beam and fabricated by the standard C-MOS processes, which can improve stress distribution non-uniform problem of conventional cantilever beam. The thickness of deposited film on its surface could reduce to several nanometers. Nanocrystalline Al thin film with thickness of sub-micrometer and nanometer were performed to observe its internal friction and energy loss response under dynamic frequency response of the cantilever beam structure generated by electrostatic force within vacuum pressure. The results show the measurement system used here can accurately measures the energy loss of thin film. The internal friction measurement results provided evidence for the grain boundary motion and dislocation motion in the nanoscale thin films. Moreover, the length scale dependence on loss mechanism of tested films was observed.
KeywordsInternal Friction Cantilever Beam Thin Metal Film Logarithmic Decrement Uniform Stress Distribution