Complementary Dual-Contact Switch Using Soft and Hard Contact Materials for Achieving Low Contact Resistance and High Reliability Simultaneously

• Published in: Journal of microelectromechanical systems 2013-08, Vol.22 (4), p.846-854
• Main Authors: Song, Yong-Ha, Kim, Min-Wu, Lee, Jeong Oen, Ko, Seung-Deok, Yoon, Jun-Bo
• Format: Article
• Language: English
• Subjects: Contact material; contact resistance; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Mechanical instruments, equipment and techniques; MEMS switch; microelectromechanical systems (MEMS) relay; Micromechanical devices and systems; microswitch; Physics; reliability
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2013.2248125

This paper reports a dual-contact microelectromechanical switch, which consists of two contacts in a single switch: one with a soft contact material and the other with a hard contact material to achieve low contact resistance and high reliability at the same time under hot switching conditions. In a single switching operation, the proposed dual-contact switch makes contact twice in sequence, where the first contact is made with a hard contact material (Pt-to-Pt) that can withstand an abrupt hot switching condition (high electric field or micro-arcing). The second contact is then accomplished with the soft contact material (Au-to-Au) that has low-contact resistance, through which most of the current flows. In contrast, when the switch releases contact, the Au-to-Au contact is initially detached, and this is followed by the release of the Pt-to-Pt contact. In this way, the dual-contact switch showed longer lifetime than that of a single Au-to-Au contact-only switch by up to fortyfold, and even better lifetime than that of a single Pt-to-Pt contact-only switch by more than two times in open laboratory environments (unpackaged). At the same time, contact resistance of the dual-contact switch was under 0.3 Ω at 50 V of the gate voltage, which is more than seven times smaller than that of the single Pt-to-Pt contact-only switch (2.2 Ω), due to the Au-to-Au contact sub-switch (the contact resistance of the single Au-to-Au contact-only switch was 2.2 Ω).