A team from the University of Bristol have developed a new type of nanoelectromechanical relay to enable reliable high-temperature, non-volatile memory.
The team say the invention is an important development for all-electric vehicles and more-electric aircraft which require electronics with integrated data storage that can operate in extreme temperatures with high energy efficiency.
Dr Dinesh Pamunuwa, who leads a group that carries out research in the field of Microelectronics at the University of Bristol and is the lead investigator, said: "This is a truly exciting development as the need to develop technology that reduces our dependency on fossil fuels increases. This relay operation is a significant step forward in developing electronics for all-electric vehicles and energy-efficient more-electric aircraft, as well as for creating zero-standby power intelligent nodes for the IoT.”
As transistor leakage current increases with temperature, nanoelectromechanical relays have emerged as a promising alternative to transistors for such applications. However, until now, a reliable and scalable non-volatile relay that retains its state when powered off, to implement memory, has not been demonstrated.
Dr Pamunuwa, explained: "Part of the challenge is the way electromechanical relays operate; when actuated, a beam anchored at one end moves under an electrostatic force. As the beam moves, the airgap between the actuation electrode and beam rapidly reduces while the capacitance increases. At a critical voltage called the pull-in voltage, the electrostatic force becomes much greater than the opposing spring force and the beam snaps in. This inherent electromechanical pull-in instability makes precise control of the moving beam, critical for non-volatile operation, very difficult.”
Now, though, the team have demonstrated a rotational relay that maintains a constant airgap as the beam moves, eliminating this electromechanical pull-in instability.
Using this relay, they have succeeded in demonstrating the first high-temperature non-volatile nanoelectromechanical relay operation, at 200°C.
The work, which is reported in Nature Communications, was carried out in collaboration with the University of Southampton and the Royal Institute of Technology, Sweden.