Anchor-free NEMS non-volatile memory cell for harsh environment data storage

Abstract

This work demonstrates a novel anchor-free nano-electromechanical (NEMS) based nonvolatile memory cell, suitable for high temperature (T ≤ 300 °C) and radiation prone harsh environment applications. The anchor-free circular metal beam is actuated by electrostatic force and is held in one of the bi-stable memory states by adhesion force between two smooth metal surfaces in contact. Smooth metal layers form strong van der Waals stiction between two surfaces in contact and memory detection (Logic-'1' / Logic-'0') is obtained by detecting the conductance between two fixed contacts. This anchor-free design offers highest density (9F 2 footprint) compared to other mechanical memory devices reported to date.

Digital Nanoelectromechanical Non-Volatile Memory Cell

“…While ferroelectric random-access memory (FRAM) can go up to 125 • C [3] and correlated electron random access memory (CeRAM) has been reported to work up to 300 • C [4], uniquely, nanoelectromechanical (NEM) relays are simultaneously high temperature capable [5] and radiation hard [6] with zero standby power. However, to date, while single devices have been demonstrated [7]- [11], any memories or memory cells are one-time programmable [12] or require CMOS for access [13]- [15]. Our own prior work discussed implementation of a fully mechanical relay-based memory cell, but this could not be operated as intended due to the beams of the relays collapsing to the substrate when actuated with the required access pattern [16].…”

Theory, Design, and Characterization of Nanoelectromechanical Relays for Stiction-Based Non-Volatile Memory

“…Nanoelectromechanical (NEM) relays, by contrast, have zero sleep current, a steep subthreshold slope [1], [2], [3], [4], [5], [6], as well as the capability to operate at elevated temperatures [7] and radiation levels [8] where transistors either work suboptimally or not at all. Non-volatile operation of NEM relays has been demonstrated using a variety of designs and schemes, including charge storage in a floating gate to alter the pull-in voltage [9], [10], and stiction between contacting surfaces [11], [12], [13]. We recently demonstrated a stiction-based bistable NEM relay with a semicircular beam that eliminates electromechanical pull-in instability [14], allowing precise electrostatic control of the beam when switching between two stable states (please see Table 1 in [14] for a comparison between electrostatic nonvolatile relays).…”