A new test facility for efficient evaluation of MEMS contact materials

• Published in: Journal of micromechanics and microengineering 2007-09, Vol.17 (9), p.1788-1795
• Main Authors: Yang, Z, Lichtenwalner, D, Morris, A, Menzel, S, Nauenheim, C, Gruverman, A, Krim, J, Kingon, A I
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Physics; Precision engineering, watch making; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0960-1317; 1361-6439
• DOI: 10.1088/0960-1317/17/9/006

A novel test facility for the efficient evaluation of microelectromechanical system (MEMS) switches and the development of alternative contact materials is described. The facility utilizes the upper cantilever from commercial MEMS contact switches, and tests these against alternative bottom contact materials within a modified atomic force microscope (AFM). The test closely approximates the real switch, but can accommodate a wider range of test conditions and contact materials. The facility allows alternative contact materials to be easily and quickly incorporated, and therefore evaluated by measuring the number of cycles to failure. The evolution of the wear surfaces of the switch contact materials under test can also be easily examined. In order to demonstrate the facility, the evolution of the contact resistance and wear of a commercial RF MEMS cantilever with Au contacts was monitored under accelerated test conditions, comparing the behavior of Au bottom contacts to an alternative Au-Ni alloy contact material. The Au-Ni (20 at.%) alloy displayed reduced wear rates and improved switch cycle lifetimes compared to pure Au, while retaining acceptable values of contact resistance.