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

Paper MN-TuM5
NEMS and AFM Cantilevers Synthesized from Metal Nanocomposites

Tuesday, November 14, 2006, 9:20 am, Room 2007

Session: Material Aspects of MEMS and NEMS
Presenter: C. Ophus, Univ. of Alberta, Canada
Authors: C. Ophus, Univ. of Alberta, Canada
Z. Lee, NCEM, Lawrence Berkeley National Lab
E. Luber, Univ. of Alberta, Canada
N. Nelson-Fitzpatrick, Univ. of Alberta, Canada
R. Mohammadi, Univ. of Alberta, Canada
C. Gilkison, Univ. of Alberta, Canada
L.M. Fischer, Univ. of Alberta, Canada
S. Evoy, Univ. of Alberta, Canada
V. Radmilovic, NCEM, Lawrence Berkeley National Lab
U. Dahmen, NCEM, Lawrence Berkeley National Lab
D. Mitlin, Univ. of Alberta, Canada
Correspondent: Click to Email
While metal films, such as Ni, Ag, Pd and Al, have been used in a variety of electronic and MEMS devices, they have had limited applications in the field of cantilever-based sensing or as AFM cantilevers. Despite several major advantages over insulators and semiconductors (optically reflecting, tough-ductile, electrically conducting), metals are notoriously difficult to pattern or release due to their high stress state, large surface roughness and low strength. We were able to overcome these limitations by using room temperature co-sputtering to synthesize nanocomposite alloy films with unique microstructures and properties. The aim of this report is to describe the device applications, the mechanical properties and the microstructure of Ni-X, Ag-X, Pd-X (where X is one or more alloy addition) and Al-Mo nanocomposite thin films. We fabricated a range of compositions and microstructures of these alloys by co-sputtering from different metal targets. Nanoindentation tests indicate that the hardness of the fabricated materials is more than an order of magnitude higher than that of conventional metal films. In addition, within a certain compositional range, the nanocomposites are under relatively low stress and possess near atomic-level smoothness. The properties of the nanocomposites are discussed in relation to the materials' microstructure, as characterized by TEM, SEM, AFM and XRD analysis. Using the microstructurally optimized versions of these alloys, we fabricated free-standing nano-scale cantilevers down to approximately 4 nm thickness. These were to our knowledge the thinnest cantilevers ever achieved both for metals and for semiconductors. We tested these devices in vibrational resonance mode, as well as further processing them into AFM-usable geometries that included both the cantilever and the tip.