ECRAM Contact-Layer Joule Heating for Ion Transport

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Solution Overview

Problem

Conventional neuromorphic computing devices using RRAM and PCM require large voltages and currents, exhibit nonlinear behavior, and have low channel resistance, making them inefficient and difficult to scale into large arrays. ECRAM devices face energy inefficiency due to the need for separate heating circuitry and complex fabrication, limiting areal density.

Innovation Solution

An ECRAM device design that heats the contact layer using Joule heating, eliminating the need for separate heating circuitry, and facilitates ion transport between the ionic reservoir and channel layers through voltage application, achieving linear and symmetric conductance changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate heating circuitry is added to ECRAM devices to enable ion transport, then ion transport capability is improved, but device complexity and areal density are worsened

Engineering Contradiction:

Improveion transport capabilityVSAvoidheating circuitry complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The heating function is merged with the existing contact layer structure. The contact layer serves dual purposes: as an electrical contact and as a heating element through Joule heating. This eliminates the need for separate heating circuitry while maintaining ion transport capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The contact layer is given multi-functionality by enabling it to perform both electrical contact and thermal heating functions. By applying voltage across the contact layer, it generates heat through its inherent resistance, thereby serving as both an electrical and thermal component.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separate heating circuitry is added to ECRAM devices to enable ion transport, then ion transport capability is improved, but areal density is worsened

Engineering Contradiction:

Improveion transport capabilityVSAvoidareal density

Core Design Contradiction:

Adaptability or versatilityVSArea of moving object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If RRAM and PCM devices are used for neuromorphic computing, then analog memory functionality is achieved, but energy efficiency and scalability are worsened

Engineering Contradiction:

Improveanalog memory functionalityVSAvoidenergy efficiency

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The invention changes the operational parameters by using Joule heating in the contact layer to achieve the required temperature for ion transport. This approach reduces the energy required compared to separate heating circuits, as the heating is localized and integrated into the device structure.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The ECRAM device achieves improved energy efficiency, reduced circuit complexity, and higher areal density compared to conventional ECRAM devices, with state retention for several days without additional energy input.

Implementation Method 1

a first voltage is applied across the contact layer of the ECRAM device, such that electron current travels laterally across the contact layer, thereby heating the contact layer by way of Joule heating

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS12446479B1Electrochemical random access memory device with contact layer as a heat source

Publication Date: 2025.10.14 NATIONAL TECHNOLOGY & ENGINEERING SOLUTIONS OF SANDIA LLC

AI summary

Technologies related to an electrochemical random access memory (ECRAM) device are described herein. The ECRAM device includes a channel layer, an electrolyte layer, a reservoir layer, and a conductive contact layer, where the conductive contact layer is in contact with the reservoir layer. A voltage source is coupled to the contact layer and is configured to cause current to flow laterally across the contact layer from one side to another, resulting in the contact layer emitting heat by way of Joule heating. When the ECRAM device is heated to a sufficiently high temperature, a second voltage is applied across the stack of layers, thereby causing ion transport between the reservoir layer and the channel layer.