Single-contact, four-terminal microelectromechanical relay for efficient digital logic

Nano and microelectromechanical relays can be used in lieu of transistors to build digital integrated circuits that can operate with zero leakage current at high operating temperatures and radiation levels. Four-terminal (4-T) relays facilitate efficient logic circuits with greatly reduced device counts compared to three-terminal (3-T) relay implementations. Existing 4-T relays, however, require two moving contacts to simultaneously land on two stationary electrodes, which can adversely impact reliability, or have complex out-of-plane fabrication methods that can reduce yield and increase cost while having poor scalability. In this work an in-plane four-terminal relay with a single moving contact is demonstrated for the first time, through successful fabrication and characterization of prototypes with a critical dimension of 1.5 µm. Body biasing is shown to reduce the pull-in voltage of this 4-T relay compared to a 3-T relay with the same architecture and footprint. The potential of the 4-T relay to build efficient logic circuits is demonstrated by fabricating and characterizing a 1-to-2 demultiplexer (DEMUX) circuit using only two devices, a saving of eight devices over a 3-T relay implementation

Digital Nanoelectromechanical Non-Volatile Memory Cell

Nanoelectromechanical relays are inherently radiation hard and can operate at high temperatures. Thus, they have potential to serve as the building blocks in nonvolatile memory that can be used in harsh environments with zero standby power. However, a reprogrammable memory cell built entirely from relays that can be operated with a digital protocol has not yet been demonstrated. Here, we demonstrate a fully mechanical digital non-volatile memory cell built from in-plane silicon nanoelectromechanical relays; a 7-terminal bistable relay utilizes surface adhesion forces to store binary data without consuming any energy, while 3-terminal relays are used for read and write access without the need for CMOS. We have optimized the designs to prevent collapse to the substrate under actuation and recorded voltages of 13, 13.2 and 27V for programming, read and reprogramming operations. This non-volatile memory cell can potentially be used to build embedded memories for edge applications that have stringent temperature, radiation and energy constraints

Nanoelectromechanical analog-to-digital converter for low power and harsh environments

State of the art analog to digital conversion at the edge prioritises either low power consumption, or environmental resilience. Nanoelectromechanical relays show promise as a solution to both with low leakage current and operation within elevated temperatures and radiation levels. This paper introduces an analog to digital flash converter design constructed from four- terminal nanoelectromechanical relays, each selectively biased to partition the voltage domain. Supported by three-terminal relays forming a binary encoder, 2-bit and 3-bit implementations of the design are simulated in Cadence to give estimates for sampling rates (444 kHz,278 kHz) and power consumption (15.58 µW,32.95 µW)

Erratum:Integrated 4-terminal single-contact nanoelectromechanical relays implemented in a silicon-on-insulator foundry process (Nanoscale (2023) DOI: 10.1039/d3nr03429a)

The authors regret the omission of one corresponding author, Dinesh Pamunuwa, from the original manuscript. The corrected list of authors and affiliations for this paper is as shown above. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.</p