Nano-crystalline graphite for reliability improvement in MEM relay contacts

Sunil Rana, Jamie Reynolds, Ting Ling, Muhammed Shamsudin, Suan Pu, Harold Chong, Dinesh Pamunuwa*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

26 Citations (Scopus)
262 Downloads (Pure)


Micro- and Nano-electromechanical (MEM/NEM) relays can operate with zero-leakage at far higher temperatures and levels of radiation than transistors, but have poor reliability. This work demonstrates improvement in reliability of MEM
relays using nano-crystalline graphite (NCG)-coated contact surfaces. The high stability of NCG in ambient air, along with its low surface energy, appear to make it an ideal contact material. NCG-coated relays achieved over 2.8 million fast, hot-switching cycles with a drain current of at least 5 ➭A and on-resistance under 17 kΩ, in ambient air. The relays also were tested in slow, hot-switching cycles designed to increase the electrical stress on the contact, and consistently achieved on-currents up to 50 uA or the imposed current limit without failure. The eventual cause of failure appeared to be mechanical stress on the NCG layer over repeated cycling causing degradation. Increasing the layer thickness is expected to further improve the contact reliability. The relays are scalable and can be used as micro- or nano-scale switches in electronic components designed for very high temperatures and levels of radiation.
Original languageEnglish
Pages (from-to)193-199
Number of pages7
Early online date9 Mar 2018
Publication statusPublished - 1 Jul 2018

Bibliographical note

Invention protected with UK patent GB2548164.

Structured keywords

  • Photonics and Quantum


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