Microrelays With Bidirectional Electrothermal Electromagnetic Actuators and Liquid Metal Wetted Contacts

Microrelays with liquid metal wetted contacts have been demonstrated using bidirectional electrothermal electromagnetic actuators. These relays were fabricated with the Metal MUMPs foundry process, which has a 20-mum-thick nickel structural layer. The operating voltage is under 0.5 V. The measured breakdown voltage and off-state resistance are greater than 200 V and 100 MOmega, respectively, and the gold-to-gold contact resistance is around 0.3 Omega. When the contacts are wetted with liquid gallium alloy (melting point at -20degC), the measured contact resistance can be as low as 0.015 Omega. As such, these bidirectional relays could have potential applications in high-power switching systems with low contact resistance using liquid metal wetted contacts.