Multi-pole NEM relays and multiple-bits-per-cell RRAM for efficient 3-D ICs

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Abstract/Contents

Abstract
In this dissertation, I present techniques for improving the power, performance, and area of integrated circuits (ICs) through 3-D integration of two emerging nanotechnologies: (1) resistive random-access memory (RRAM), a non-volatile memory with multiple-bits-per-cell storage capability, and (2) nanoelectromechanical (NEM) relays, nano-scale mechanical relays that can be actuated electrostatically. In modern ICs for edge computing, data movement between on and off-chip memories typically consumes a large fraction of the total power. Dense, non-volatile embedded memory can reduce/eliminate off-chip data movement by keeping frequently-read application data always on chip. RRAM is a good candidate for such a memory, especially because it can store multiple bits per cell, achieving high density on-chip storage. However, efficient and reliable operation with multiple-bits-per-cell RRAM has been a challenge due to (1) stochastic device behavior during programming that results in large pulse counts with traditional write-verify methods, and (2) reliability issues arising from resistance relaxation. Towards the goal of achieving efficient and reliable multiple-bits-per-cell RRAM, I present three contributions: (1) range-dependent adaptive resistance (RADAR) tuning, a fast and energy-efficient programming method for multiple-bits-per-cell RRAM that uses an adaptive combination of coarse- and fine-grained cell resistance tuning, yielding a 2.4x reduction in pulse count over prior methods, (2) characterization of resistance relaxation behavior in three RRAM technologies and analysis of its implications for multiple-bits-per-cell storage, and (3) efficient multiple-bits-per-cell embedded RRAM (EMBER), the first demonstration of a fully-integrated multiple-bits-per-cell RRAM macro. EMBER contains a multiple-bits-per-cell read and write controller with a high degree of flexibility that enables good level allocation (mitigating reliability issues from resistance relaxation) and programming scheme optimization (yielding low-energy, low-latency multiple-bits-per-cell writes). Finally, in reconfigurable ICs, in addition to the memories, the routing fabric consumes a large fraction of the overall area and power. I demonstrate that replacing CMOS routing switches with 3-D integrated multi-pole nanoelectromechanical (NEM) relays in a coarse-grained reconfigurable array (CGRA) can achieve 19% lower area and 10% lower power at iso-performance.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2024; ©2024
Publication date 2024; 2024
Issuance monographic
Language English

Creators/Contributors

Author Levy, Akash
Degree supervisor Raina, Priyanka, (Assistant Professor of Electrical Engineering)
Thesis advisor Raina, Priyanka, (Assistant Professor of Electrical Engineering)
Thesis advisor Howe, Roger Thomas
Thesis advisor Wong, Hon-Sum Philip, 1959-
Degree committee member Howe, Roger Thomas
Degree committee member Wong, Hon-Sum Philip, 1959-
Associated with Stanford University, School of Engineering
Associated with Stanford University, Department of Electrical Engineering

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Akash Levy.
Note Submitted to the Department of Electrical Engineering.
Thesis Thesis Ph.D. Stanford University 2024.
Location https://purl.stanford.edu/td360bh0033

Access conditions

Copyright
© 2024 by Akash Levy
License
This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).

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