AVS 53rd International Symposium
    MEMS and NEMS Tuesday Sessions
       Session MN-TuA

Paper MN-TuA3
Fabrication and Testing of NEMS Components Made from Nanocomposite Al-Mo Films

Tuesday, November 14, 2006, 2:40 pm, Room 2007

Session: Fabrication and Characterization of MEMS and NEMS
Presenter: D. Mitlin, University of California
Authors: D. Mitlin, University of California
Z. Lee, Lawrence Berkeley National Laboratory
C. Ophus, University of Alberta, Canada
N. Nelson-Fitzpatrick, University of Alberta, Canada
L.M. Fischer, University of Alberta, Canada
S. Evoy, National Institute of Nanotechnology
U. Dahmen, Lawrence Berkeley National Laboratory
V. Radmilovic, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
Despite several major advantages over semiconductor-based NEMS components (optically reflecting, electrically conducting, tough-ductile), metal-based components with nm-scale dimensions are notoriously difficult to achieve due to their large surface roughness and grain size, high stress state, and low strength. We were able to overcome these limitations by using room temperature co-sputtering to synthesize nanocomposite alloy films of Al-Mo. We now report having successfully fabricated fully released NEMS cantilevers of various geometries from such metallic materials. At a device thickness as low as 4 nm, these are the thinnest released metal cantilevers reported in the literature to date. A systematic investigation of microstructure and properties as a function of Mo content resulted in an optimum film composition of Al-32at%Mo, with a unique microstructure comprised of a dense distribution of nm-scale Mo crystallites dispersed in an amorphous Al-rich matrix. These films were found to exhibit unusually high nanoindentation hardness and a very significant reduction in roughness compared to pure Al, while maintaining resistivity in the metallic range. A single-anchored cantilever 5 µm long, 800 nm wide and 20 nm thick showed a resonance frequency of 608 kHz, yielding a Young's modulus of 112 GPa, in good agreement with a reduced modulus of 138 GPa measured by nanoindentation.