Graphite coating improves nano-relays

Graphite coating improves nano-relays

Technology News |
Researchers from the Universities of Bristol and Southampton, in collaboration with Microsemi Corp., have demonstrated reliable operation of microelectromechanical relays by coating the contacts with nanocrystalline layers of graphite.
By Peter Clarke

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The researchers have shown how nanocrystalline graphite at a thickness of tens of nanometers protects the relay contacts against degradation over millions of switching cycles while maintaining a reliable electrical contact.

Although relays have been designed out of many applications in favour of solid-state transistor switches, there are applications where the low leakage current of transistors even when “off” is problematic. Micro and nanoelectromechanical relays have effectively zero leakage current and can operate at much higher temperatures and levels of radiation than solid-state transistors.

Such miniaturised relays have potential to preserve low power standby within integrated sensing, processing and actuation nodes.

The relays were designed by Sunil Rana, a senior postdoctoral research associate at Bristol. The work was carried out as a collaboration between Bristol’s Microelectronics research group led by Dinesh Pamunuwa, and Harold Chong’s group at Southampton University, with Jamie Reynolds and Suan Hui Pu.

“The relays can withstand temperatures over 225 degrees C and can easily absorb radiation doses that are two orders of magnitude higher than transistors are able to withstand. The challenge has been to make them reliable, and these thin films of nano-crystalline graphite effectively act as a conducting solid lubricant, protecting the relay electrodes as they physically make and break contact millions of times,” said Pamunuwa, in a statement.

Nano-crystalline graphite for reliability improvement in MEM relay contacts’ by Sunil Rana, Jamie D. Reynolds, Ting Y. Ling, Muhammed S. Shamsudin, Suan Hui Pu, Harold M.H. Chong and Dinesh Pamunuwa, appeared in the publication Carbon.

Related links and articles:

www.bristol.ac.uk

www.southampton.ac.uk

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