High-reliability, high-performance RF micromachined switch using liquid metal

Existing mechanical relays have reliability-related issues including unstable contact resistance and limited cycle life. These problems are caused by mechanical fatigue and wearing of the contact surfaces. In the liquid metal micro switch (LiMMS), we employ a liquid-liquid contact to address these i...

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Bibliographic Details
Published in:Journal of microelectromechanical systems 2005-04, Vol.14 (2), p.214-220
Main Authors: Kondoh, Y., Takenaka, T., Hidaka, T., Tejima, G., Kaneko, Y., Saitoh, M.
Format: Article
Language:English
Subjects:
Contact
Contact resistance
Devices
Fatigue
Gas expansion
Glass
Glass substrates
Heaters
Liquid metals
Microchannel
Noise levels
Prototypes
Radio frequencies
Radio frequency
Relays
Substrates
Surface resistance
Switches
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Summary:Existing mechanical relays have reliability-related issues including unstable contact resistance and limited cycle life. These problems are caused by mechanical fatigue and wearing of the contact surfaces. In the liquid metal micro switch (LiMMS), we employ a liquid-liquid contact to address these issues. The switching operation is achieved by forming a gap in the liquid metal using gas expansion. Our prototype has a microchannel on a glass substrate to hold a tiny amount of mercury, 0.15 mm in width and 0.1 mm in height, and TaN thin-film heaters on a ceramic substrate to expand the operating gas by heating. The substrates are bonded together and the total size of the device is 5/spl times/5/spl times/1.4 mm. We successfully demonstrated 70-m/spl Omega/ on-resistance, 1 ms-switching speed, the ability to handle up to 1 A of dc current and over 1/spl times/10/sup 8/ cycle operation. LiMMS also has good RF performance, better than 1 dB insertion loss, and better than 20 dB isolation up to 18 GHz.
ISSN:1057-7157
1941-0158
DOI:10.1109/JMEMS.2004.839604