Nanoelectronic Programmable Synapses Based on Phase Change Materials for Brain-Inspired Computing

Abstract

Brain-inspired computing is an emerging field, which aims to extend the capabilities of information technology beyond digital logic. A compact nanoscale device, emulating biological synapses, is needed as the building block for brain-like computational systems. Here, we report a new nanoscale electronic synapse based on technologically mature phase change materials employed in optical data storage and nonvolatile memory applications. We utilize continuous resistance transitions in phase change materials to mimic the analog nature of biological synapses, enabling the implementation of a synaptic learning rule. We demonstrate different forms of spike-timing-dependent plasticity using the same nanoscale synapse with picojoule level energy consumption.

All-dielectric phase-change reconfigurable metasurface

“…The latter can also be achieved through an accumulation of sub-threshold (including fs laser pulse) excitations, facilitating reproducible "greyscale" and neuromorphic switching modes of interest for all-optical data and image processing, and harnessed recently for direct, reversible laser writing of planar optical elements and short/mid-wave IR metamaterials in a chalcogenide thin film. [23][24][25][26] Here, we demonstrate structurally engineered highquality near-infrared transmission and reflection resonances in planar (300 nm thick) dielectric nano-grating metasurfaces of amorphous germanium antimony telluride (Ge 2 Sb 2 Te 5 or GST -a widely used composition in data storage applications), and the non-volatile switching of these resonances via laser-induced crystallization of the chalcogenide. We employ nano-grating array metasurface patterns of subwavelength periodicity ( Fig.…”

Crystal growth within a phase change memory cell

“…In particular, phase change memory (PCM) has recently emerged as the most promising new nonvolatile solid-state memory technology [1][2][3] . Phase-change materials are also being investigated as building blocks of neuromorphic computing hardware [4][5][6] .…”

Threshold switching via electric field induced crystallization in phase-change memory devices

“…Electrical phase change memories (PCMs) are of much topical interest as a potential next-generation non-volatile memory technology 1,2 and for possible advanced applications in such areas as arithmetic and neuromorphic processing. 3,4 PCMs utilize a reversible switching transition from a high-resistance (amorphous) state to low-resistance (crystalline) state in order to store data. A characteristic feature of the electrically driven amorphous to crystalline (SET) transition is the existence of a threshold electric field that must be exceeded for switching to occur.…”