Single‐Contact, Four‐Terminal Microelectromechanical Relay for Efficient Digital Logic

Abstract

Publisher's PDF, also known as Version of record License (if available): CC BY Link to published version (if available): 10.1002/aelm.202200584 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Wiley at Full-text PDF (final published version) .Please refer to any applicable terms of use of the publisher.

Integrated 4-terminal single-contact nanoelectromechanical relays implemented in a silicon-on-insulator foundry process

“…7,8 In this way, the 4-T relay design enables logic circuits to be constructed with far fewer devices compared to transistorbased and 3-T NEM relay-based logic circuits. 9 Also, the decoupling of the actuation and signal voltages allows the pull-in voltage of 4-T NEM relays to be reduced by employing bodybiasing, where the beam or gate has a static voltage bias applied to reduce the voltage swing required for actuation. Although basic NEM relay-based logic functions were introduced over a decade ago, [10][11][12][13] reliable miniaturization and integration methods for making NEM relay-based integrated circuits with multi-layer metal interconnect stacks have not been demonstrated.…”

“…The 4-T NEM relay is actuated by applying a voltage between the gate and body terminals, thereby inducing electrostatic attraction between them, and deflecting the mechanically connected beams of the body and source terminals to establish an electrical contact between the source and the drain terminals. A 4-T relay with a similar architecture was demonstrated by Reynolds et al , 9 but their focus was on proof-of-concept of the relay principle and the resulting circuit efficiencies using larger microscale relay prototypes fabricated on an SOI wafer. Recently, we presented the fabrication of a 4-T NEM relay in the Si device layer of SOI substrate without metal interconnects.…”

“…15 In contrast, in this work we demonstrate the first nanoscale 4-T NEM relay integrated with multi-layer metal interconnects, featuring a ∼10× reduction in critical dimension compared to the relays presented in ref. 9 (from 2 μm down to 200 nm). These advancements in integration and miniaturization are pivotal for the development of large-scale integrated NEM relay-based circuits.…”

Fully Microelectromechanical Non-Volatile Memory Cell

“…Figure 3: Combining a tiled array of memory cells with a multiplexer [11] to produce a look-up-table memory. All cells are simultaneously written to or read from through the shared "write" signal, with the multiplexer selecting a single value from the array.…”

“…By contrast, this work uses a nonvolatile 7-terminal (7-T) rotational relay as the storage device [8], [9], and combines it with two 3-terminal (3-T) relays [10] to produce the first all MEM storage cell including read and write circuitry. As this cell does not depend on stored charge or CMOS addressing circuitry, it can be tiled with the aid of a relay-based multiplexer [11] to produce a fully MEM, addressable memory that consumes near zero standby power and is resilient to high temperatures and high levels of radiation.…”