[Paper Review] Memristor Crossbars with 4.5 Terabits-per-Inch-Square Density and Two Nanometer Dimension

Shuang Pi, Can Li+5 more|arXiv (Cornell University)|Apr 26, 2018

Advanced Memory and Neural Computing50 references155 citations

TL;DR

The paper demonstrates memristor crossbars achieving up to 4.5 Tb/in^2 density with 2×2 nm^2 devices, capable of switching with tens of nanoamperes. This presents a highly dense, power-efficient storage/processing solution.

ABSTRACT

Memristor is a promising building block for the next generation nonvolatile random access memory and bio-inspired computing systems. Organizing memristors into high density crossbar arrays, although challenging, is critical to meet the ever-growing high capacity and low energy demands of these applications especially in the big data era. Here, we construct memristor crossbars with a single-layer density up to 4.5 terabits per inch square, an order of magnitude denser than the state- of-the-art 64-layer triple level cell NAND flash technology. The memristors in the crossbars are 2 $ imes$ 2 nm$^2$ in size, capable of switching with tens of nano ampere electric current. The densely packed memristor crossbars of extremely small working devices provides a power-efficient solution for high density information storage and processing.

Motivation & Objective

• Motivate high-density, energy-efficient memory and neuromorphic computing using memristor crossbars.
• Demonstrate a single-layer crossbar achieving unprecedented bit density.
• Show device dimensions and switching current suitability for scalable integration.

Proposed method

• Fabricate memristor crossbars with 2×2 nm^2 devices.
• Achieve and characterize a single-layer density up to 4.5 terabits per inch square.
• Specify switching with tens of nanoampere electric current.
• Compare density to state-of-the-art NAND flash technology (64-layer, triple level cell).

Experimental results

Research questions

• RQ1 Can memristor crossbars at sub-3 nm device dimensions realize terabits-per-square-inch densities in a single layer?
• RQ2 What is the switching current required for such densely packed memristors, and is it power-efficient for large-scale integration?
• RQ3 How does the achieved density compare to contemporary high-density memory technologies?
• RQ4 What are the implications for storage and processing efficiency in neuromorphic or big-data applications?

Key findings

• Memristor crossbars with 4.5 Tb/in^2 density are demonstrated in a single layer.
• Memristors are 2×2 nm^2 in size and switch with tens of nanoamperes.
• The demonstrated density is an order of magnitude higher than the state-of-the-art 64-layer TLC NAND flash technology.
• Dense crossbars offer a power-efficient solution for high-density information storage and processing.