PdNeuRAM: forming-free, multi-bit Pd/HfO2 ReRAM for energy-efficient neuromorphic computing

TL;DR

This paper introduces PdNeuRAM, a forming-free, multi-bit HfO2-based ReRAM that operates at low voltages, reduces variability, and enhances energy efficiency for neuromorphic computing.

Contribution

The study presents a novel Pd-O-Hf configuration enabling forming-free operation and multi-bit functionality in ReRAM, reducing energy consumption and variability.

Findings

Reduces programming energy by 43% and reading energy by 73%.

Supports multi-bit operation with reduced variability.

Operates at low voltages without electroforming.

Abstract

Memristor technology shows great promise for energy-efficient computing, yet it grapples with challenges like resistance drift and inherent variability. For filamentary Resistive RAM (ReRAM), one of the most investigated types of memristive devices, the expensive electroforming step required to create conductive pathways results in increased power and area overheads and reduced endurance. In this study, we present novel HfO2-based forming-free ReRAM devices, PdNeuRAM, that operate at low voltages, support multi-bit functionality, and display reduced variability. Through a deep understanding and comprehensive material characterization, we discover the key process that allows this unique behavior: a Pd-O-Hf configuration that capitalizes on Pd innate affinity for integrating into HfO2. This structure actively facilitates charge redistribution at room temperature, effectively eliminating the need for electroforming. Moreover, the fabricated ReRAM device provides tunable resistance states for dense memory and reduces programming and reading energy by 43% and 73%, respectively, using spiking neural networks (SNN). This study reveals novel mechanistic insights and delineates a strategic roadmap for the realization of power-efficient and cost-effective ReRAM devices.