Resistance Change Device Dual-Layer Ion Transport

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Solution Overview

Problem

In resistance change devices, the use of high resistivity positive-electrode active material layers results in large resistance values and small readout currents, leading to malfunction and insufficient resistance changes, making it difficult to function effectively as a resistance change device.

Innovation Solution

A resistance change device is designed with two resistance change layers and an ion conductive layer, where the resistance of each layer changes with ion occlusion and discharge, allowing for simultaneous resistance changes and improved readout currents by connecting the layers in parallel or series, using materials like LiCoO2 and Li4Ti5O12 for the resistance change layers and Li3PO4 as the ion conductive layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high resistivity positive-electrode active material layers are used, then the resistance value increases, but the readout current becomes small leading to malfunction

Engineering Contradiction:

Improvedevice functionalityVSAvoidreadout current

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The device is divided into two separate resistance change layers (first and second layers) with different resistance characteristics. By segmenting the single-layer structure into two layers that can be connected in parallel or series, the invention achieves both high resistance change ratio and sufficient readout current, resolving the contradiction between reliability and power.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structures where the first resistance change layer and second resistance change layer are made of different materials with complementary properties. This allows one layer to provide high resistance change while the other layer compensates to maintain adequate readout current, solving the malfunction issue caused by overly high resistance.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If high resistivity materials are used to achieve sufficient resistance changes, then the resistance change ratio improves, but the readout current becomes insufficient

Engineering Contradiction:

Improveresistance change ratioVSAvoidreadout current

Core Design Contradiction:

Manufacturing precisionVSPower

Solution Approach 1:

By dividing the resistance change function across two separate layers, the invention enables one layer to specialize in achieving high resistance change ratio while the other layer ensures adequate readout current. This segmentation resolves the contradiction between manufacturing precision (resistance change ratio) and power (readout current).

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the electrical parameters by using two layers with different resistance characteristics that can be configured in parallel or series. This parameter adjustment allows optimization of both resistance change ratio and readout current simultaneously, addressing the contradiction between manufacturing precision and power.

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

This configuration reduces resistance values by one to two orders of magnitude and enhances readout currents, preventing malfunctions and improving device characteristics by ensuring sufficient resistance changes for data storage.

Implementation Method 1

an ion conductive layer that carries the ions and is provided between the first resistance change layer and the second resistance change layer

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

a first resistance change layer that occludes and discharges ions of at least one type, and resistance of the first resistance change layer changes in accordance with an amount of the ions

Methodology Applied

Scientific EffectIon occlusion and discharge: Absorption (physical)

Data Source

PatentUS11328769B2Resistance change device, manufacturing method for the same, and storage apparatus

Publication Date: 2022.05.10 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A resistance change device includes a first resistance change layer that occludes and discharges ions of at least one type, and resistance of the first resistance change layer, changes in accordance with an amount of the ions in such a manner that the resistance decreases when the ions are discharged and the resistance increases when the ions are occluded; a second resistance change layer that occludes and discharges the ions, and resistance of the second resistance change layer changes in accordance with the amount of the ions in such a manner that the resistance increases when the ions are discharged and the resistance decreases when the ions are occluded; and an ion conductive layer that carries the ions and is provided between the first resistance change layer and the second resistance change layer.