Emerging Memory Structures for VLSI Circuits

Abstract

Ever since the emergence of the electrical computer and the Von Neumann model, computer architects have adhered to a well‐structured hierarchy of memory solutions, clearly trading off performance and capacity with cost. The ubiquitous memory technologies, dominated by SRAM, DRAM, Flash, and magnetic hard disks, are each situated in a well‐defined location within this hierarchy. However, as processes have scaled into deep nanometer feature sizes and the demand for larger capacities and bandwidths increases, these traditional options face tough challenges and may be limited in their ability to continue to provide the new requirements. New technologies, such as phase change memory (PCM), magnetic RAM (MRAM), and resistive RAM (RRAM), have been researched and developed over the recent past in an attempt to meet these demands and replace some or all of the traditional technologies. In this article, the primary technologies are overviewed, including those that currently fill the memory hierarchy pyramid, the primary candidates to join or replace them in the near‐term, and a number of newer candidates that may arise as legitimate solutions in the farther term. In addition, an overview of the current state of processing within the emerging memory technologies is provided, as an attempt to break free of the traditional Von Neumann paradigm to overcome the energy and performance bottlenecks in modern systems.

A 0.11pJ/bit read energy embedded NanoBridge non-volatile memory and its integration in a 28 nm 32 bit RISC-V microcontroller units

“…8) Emerging nonvolatile memories (NVM), such as resistive RAM (ReRAM), 9) phase-change memory (PCM), 10) magnetic RAM (MRAM) 11) and ferroelectric RAM (FeRAM) 12) are promising candidates to replace the eFLASH thanks to their scalability below 10 nm. 13) Our NanoBridge (NB) (a.k. a. atom switch 14,15) ) is one of the promising candidates since its superior ON/OFF conductance ratio (>10 4 ) 16) can simplify read circuity and long read retention time at a wide temperature range of (−40 °C-150 °C) 17) leads to high read reliability.…”

Multi-Ported GC-eDRAM Bitcell with Dynamic Port Configuration and Refresh Mechanism

“…Often, such works embed processing elements within the memory to achieve what is commonly referred to as "in-memory computing" [23][24][25]. Memories constructed with emerging devices, such as resistive and magnetic RAM, are commonly used for this purpose [26][27][28]. An example of such a work is described in [29], where highly efficient storage of model weights and personalized data is securely achieved using such memories.…”