Switching Dynamics and Contact Surface Characterization for Ohmic MEMS Switches

F. Anwar, M. Munna, M.S. Hossain, P. Mahanta, T. Nandy, R.A. Coutu, Jr.
Marquette University,
United States

Keywords: MEMS, Cantilever, Bridge, switching technology, contact bounce, contact surface


Ohmic microelectromechanical systems (MEMS) switching technology shows promising performances in DC and RF applications. However, reliability is of great concern where operating cycle is > 10^9. For such many cycles, degradation of the contacts can severely affect the switching activity and thus lead to the failure of the device. Switching dynamics and contact surface physics associated with the microcontact play the key role in determining their reliability. In the macro-world, the event of multiple re-closures and multiple re-openings of contacts due to contact bounce greatly degrades the contact surface and has been classified as one of the chief factors limiting the micro-switch performance, as well as the lifetime. Circuits that require a fast response time, are particularly vulnerable to this phenomenon and this is where contact bounce in micro-switches come into play. In earlier studies it has been demonstrated that after contact bounce takes place, the number of bounce generation keeps increasing, leading to a faster rate of contact deterioration. Moreover, recently it has been demonstrated that material transfers, molten metal bridge formation, and delamination contribute to contact degradation after a certain number of switching cycles as well. The goal of this work is to investigate the effects of contact bounce on the contact surface of micro-switches using different materials and under different circuit and switching conditions. We fabricated cantilevers and bridge structures with various beam geometries using MEMS fabrication processes. The switching devices will be assembled with appropriate test setup for data collection. This study will provide guidelines for future robust microswitch design as well as the impetus for finding its applications in the broad spectrum of information and communication technology.