AVS 52nd International Symposium
    MEMS and NEMS Monday Sessions
       Session MN-MoM

Paper MN-MoM6
An SPM-Based System for Contact Reliability Characterization

Monday, October 31, 2005, 10:00 am, Room 207

Session: Processing & Characterization of Materials for MEMS & NEMS
Presenter: L. Chen, Northeastern University
Authors: L. Chen, Northeastern University
N. McGruer, Northeastern University
G. Adams, Northeastern University
R. Coutu, Air Force Research Laboratory
K. Leedy, Air Force Research Laboratory
Correspondent: Click to Email
An SPM-based test station has been established for studying reliability physics of contacts in a micromechanical switch. A wide contact force range is accessible, from nN to mN, as determined by the mechanical properties of the microfabricated contact test cantilevers. During testing the contact force, the contact adhesion, and the contact resistance are measured. Material transfer is observed with an SEM. The cycling rate can reach 200 kHz by driving a piezo actuator at resonance. The contact properties of gold, ruthenium, rhodium and platinum and gold alloy have been studied and compared. Gold-on-gold contacts typically show decreased resistance, increased adhesion, and large amount of material transfer as the number of cycles increases. Ruthenium-on-gold and ruthenium-on-ruthenium contacts have better mechanical performance, but a higher contact resistance which increases with cycling. Two different shaped contacts, flat-top and hemispherical shaped, are used to study mechanical contact degradation. This work was supported by DARPA under its HERMIT program through research grant F33615-03-1-7002 to Northeastern University.