R-RAM Interface Layer Diffusion for Delamination Prevention

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Solution Overview

Problem

Non-volatile memory systems, particularly R-RAM technology, face issues with layer delamination due to different expansion/contraction characteristics, leading to pseudo high resistance states and damage to hundreds or thousands of storage cells, necessitating a solution that enhances reliability and withstands thermal cycling.

Innovation Solution

A non-volatile memory system is fabricated by forming a dielectric layer with a hole, depositing a first electrode, applying an ion source layer, and a second electrode with an interface layer and cap layer, where the interface layer diffuses into the ion source layer at 200-450 degrees Celsius to prevent delamination, and the cap layer forms a barrier structure to accommodate reactive metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If new material and structure are used in R-RAM technology to increase memory density, then memory density is improved, but layer delamination occurs due to different expansion/contraction characteristics

Engineering Contradiction:

Improvememory densityVSAvoidlayer adhesion

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

An interface layer is introduced between the second electrode and the ion source layer to act as a mediator that prevents delamination. This intermediate layer accommodates the different thermal expansion characteristics of adjacent layers, preventing direct contact and subsequent delamination while maintaining the desired memory density.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite multi-layer structure consisting of dielectric layer, first electrode, ion source layer, interface layer, and cap layer. Each layer is carefully selected with specific material properties to ensure thermal compatibility and prevent delamination while maintaining high memory density.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the second electrode is deposited directly on the ion source layer, then manufacturing process is simplified, but delamination occurs during thermal cycling

Engineering Contradiction:

Improvedeposition processVSAvoidthermal cycling resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The interface layer serves as a necessary intermediary between the second electrode and ion source layer. Although it adds an extra deposition step, it is thin and can be deposited using standard processes, while dramatically improving thermal cycling resistance by preventing delamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interface layer is deposited in advance before final electrode formation, pre-establishing a delamination-resistant boundary. This preliminary action prevents thermal stress damage before it can occur during subsequent manufacturing or operational thermal cycling.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If reactive metals are used in the second electrode for optimal performance, then electrical performance is improved, but compatibility with manufacturing processes becomes difficult

Engineering Contradiction:

Improveelectrical performanceVSAvoidprocess compatibility

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The cap layer acts as a protective intermediary that allows reactive metals to be used in the second electrode for optimal electrical performance. This outer layer shields the reactive metals from unwanted interactions with subsequent manufacturing processes while maintaining electrical functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The second electrode structure is designed as a composite with multiple layers including the cap layer and reactive metal layers. This composite structure combines the electrical performance benefits of reactive metals with the manufacturing compatibility provided by the cap layer.

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

This approach prevents delamination of the second electrode during operational stress, maintaining low resistance and compatibility with manufacturing processes, thereby enhancing the reliability and performance of non-volatile memory systems.

Implementation Method 1

the interface layer diffuses into the ion source layer at 200-450 degrees Celsius to prevent delamination

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the cap layer forms a barrier structure to accommodate reactive metals

Methodology Applied

Scientific EffectBarrier formation:

Data Source

PatentUS10490740B2Non-volatile memory system with reliability enhancement mechanism and method of manufacture thereof

Publication Date: 2019.11.26 SONY SEMICON SOLUTIONS CORP

AI summary

A method of manufacture of a non-volatile memory system comprising: forming a dielectric layer having a hole; depositing a first electrode in the hole of the dielectric layer; applying an ion source layer over the first electrode; and depositing a second electrode over the ion source layer including: depositing an interface layer on the ion source layer, and applying a cap layer on the interface layer.