RRAM Protective Layer Prevents Silicide and Hydrogen Permeation

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Solution Overview

Problem

Conventional resistive random access memories (RRAMs) face issues with memory function deterioration due to silicide formation and hydrogen permeation, which affect the characteristics of the variable resistance layer and switching device.

Innovation Solution

A protective layer made of materials like aluminum oxide or titanium oxide is used to prevent silicide reactions and hydrogen permeation, covering the variable resistance layer and switching device, thereby maintaining the integrity of the RRAM's resistance characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a silicon oxide interlayer insulating layer is formed on both the metal oxide variable resistance layer and the diode, then the device structure is completed, but silicide forms in the interfaces causing memory function deterioration

Engineering Contradiction:

Improvedevice structure completionVSAvoidmemory function

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A protective layer made of aluminum oxide or titanium oxide is introduced as an intermediary between the silicon oxide interlayer insulating layer and the metal oxide variable resistance layer. This protective layer prevents direct contact between silicon and metal oxide, thereby preventing silicide formation while allowing the device structure to be completed. The protective layer acts as a barrier that mediates the interaction between the insulating layer and the variable resistance layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The original single-layer silicon oxide interlayer insulating structure is segmented into multiple layers: a protective layer (aluminum oxide or titanium oxide) and a silicon oxide layer. This segmentation allows each layer to perform its specific function - the protective layer prevents silicide formation while the silicon oxide layer provides insulating properties, thus resolving the contradiction between structure completion and memory function preservation.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the variable resistance layer is exposed, then the device structure is simplified, but hydrogen permeation deteriorates the characteristics of the variable resistance layer

Engineering Contradiction:

Improvedevice structureVSAvoidvariable resistance layer characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The protective layer made of aluminum oxide or titanium oxide creates an inert environment for the metal oxide variable resistance layer by forming a barrier that prevents hydrogen permeation. This inert protective environment shields the variable resistance layer from external hydrogen while maintaining a relatively simple device structure, as the protective layer can be integrated into the existing interlayer insulating structure.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Device complexity

If no protective layer is used, then the device structure is simpler, but silicide formation and hydrogen permeation cause memory function deterioration

Engineering Contradiction:

Improvedevice structureVSAvoidmemory function

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The interlayer insulating structure is transformed from a single material (silicon oxide) to a composite structure combining aluminum oxide or titanium oxide with silicon oxide. This composite material approach provides dual functionality: the aluminum oxide or titanium oxide layer prevents silicide formation and hydrogen permeation, while the silicon oxide layer provides insulating properties, thus improving reliability without significantly increasing device complexity.

Inventive Principle:

Principle #40Composite materials

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 solution effectively suppresses silicide formation and hydrogen permeation, enhancing the reliability and memory functions of RRAMs by preventing the deterioration of the variable resistance layer and switching device.

Implementation Method 1

A protective layer made of materials like aluminum oxide or titanium oxide is used to prevent silicide reactions and hydrogen permeation

Methodology Applied

Scientific EffectPhysical barrier prevention:

Implementation Method 2

The protective layer may also be a material layer for suppressing and/or preventing the permeation of hydrogen from the outside

Methodology Applied

Scientific EffectPermeation suppression: Permeation

Data Source

PatentUS8169053B2Resistive random access memories and methods of manufacturing the same

Publication Date: 2012.05.01 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided are resistive random access memories (RRAMs) and methods of manufacturing the same. A RRAM includes a storage node including a variable resistance layer, a switching device connected to the storage node, and a protective layer covering an exposed part of the variable resistance layer. The protective layer includes at least one of aluminum oxide and titanium oxide. The variable resistance layer is a metal oxide layer.