Transition Metal Oxynitride Oxygen Diffusion Barrier for Memory Stability

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Solution Overview

Problem

The existing resistance variable nonvolatile memory elements face challenges in maintaining a stable oxygen concentration profile due to thermal diffusion of oxygen in transition metal oxides during semiconductor processes, affecting the initial resistance and voltage requirements for resistance switching operations.

Innovation Solution

A nonvolatile memory element with a multi-layer structure comprising a first transition metal oxide layer, a transition metal oxynitride layer, and a second transition metal oxide layer, where the transition metal oxynitride layer acts as an oxygen diffusion barrier to maintain a desired oxygen concentration profile, even after thermal budgeting, using materials like tantalum oxide and tantalum oxynitride that are compatible with semiconductor processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple resistance variable layer structure is used, then device complexity is reduced and miniaturization is enabled, but oxygen concentration stability deteriorates due to thermal diffusion during semiconductor processes

Engineering Contradiction:

Improvememory element structureVSAvoidoxygen concentration profile

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The resistance variable layer is segmented into multiple sub-layers with different oxygen concentrations (first transition metal oxide layer with lower oxygen concentration, second transition metal oxide layer with higher oxygen concentration), allowing each layer to serve specific functions while maintaining overall stability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An oxygen diffusion barrier layer is introduced between the first and second transition metal oxide layers to prevent oxygen diffusion during thermal processes, acting as an intermediary that maintains the oxygen concentration gradient without requiring complex external control mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If thermal budget is increased to complete semiconductor processes, then manufacturing completeness is improved, but oxygen diffusion in transition metal oxide increases causing resistance value instability

Engineering Contradiction:

Improvesemiconductor process completionVSAvoidresistance value stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The oxygen diffusion barrier layer serves as a protective intermediary that allows standard thermal semiconductor processes to be completed while preventing harmful oxygen diffusion that would otherwise occur at these temperatures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the material parameter of the barrier layer to have low oxygen diffusivity at semiconductor processing temperatures, allowing thermal budgets to be increased for process completeness without compromising resistance stability

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 enhances the heat resistance and stability of the resistance variable layer, allowing for consistent resistance switching operations without significant changes in initial resistance, even under increased thermal budgets, thereby improving the reliability and performance of nonvolatile memory devices.

Implementation Method 1

The transition metal oxynitride layer is provided between the first transition metal oxide layer and the second transition metal oxide layer... the transition metal oxynitride layer acts as an oxygen diffusion barrier to maintain a desired oxygen concentration profile

Methodology Applied

Scientific EffectOxygen diffusion barrier: Diffusion Barrier

Implementation Method 2

its resistance value changes from a high-resistance value to a low-resistance value or from the low-resistance value to the high-resistance value, for example, by applying electric pulses thereto

Methodology Applied

Scientific EffectResistance switching:

Data Source

PatentUS8441060B2Nonvolatile memory element and nonvolatile memory device incorporating nonvolatile memory element

Publication Date: 2013.05.14 PANASONIC SEMICON SOLUTIONS CO LTD

AI summary

A nonvolatile memory element includes a first electrode (103) formed on a substrate (101), a resistance variable layer (108) and a second electrode (107), wherein the resistance variable layer has a multi-layer structure including at least three layers which are a first transition metal oxide layer (104), a second transition metal oxide layer (106) which is higher in oxygen concentration than the first transition metal oxide layer (104), and a transition metal oxynitride layer (105). The second transition metal oxide layer (106) is in contact with either one of the first electrode (103) and the second electrode (107). The transition metal oxynitride layer (105) is provided between the first transition metal oxide layer (104) and the second transition metal oxide layer (106).