Resistive Switching Memory Stack 3D Integration via ALD

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current resistive random access memory (RRAM) technologies are not suitable for three-dimensional structures due to limitations in controlling oxygen vacancy concentration, which is crucial for their functionality in neuromorphic computing and high-density memory applications.

Innovation Solution

A resistive switching memory stack is developed using Atomic Layer Deposition (ALD) techniques, comprising a bottom electrode, an oxide layer, and a top electrode with a metal layer stack that includes a transition metal alloy (M)AlC, where the oxygen vacancy concentration is controlled by the thickness of the metal layers and the percentage of specific metals, enabling precise tuning for three-dimensional structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If Physical Vapor Deposition (PVD) is used to deposit ReRAM stacks to control oxygen vacancy concentration, then the oxygen vacancy concentration can be controlled, but application to three-dimensional (3D) structures is prevented

Engineering Contradiction:

Improveoxygen vacancy concentration controlVSAvoidapplicability to 3D structures

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the physical vapor deposition (PVD) process with a chemical vapor deposition (CVD) process. This substitution allows the formation of metal oxide layers on three-dimensional structures while maintaining control over oxygen vacancy concentration through chemical reactions during deposition, thereby resolving the contradiction between manufacturing precision and adaptability to 3D structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the deposition method from PVD to CVD, which fundamentally alters the deposition mechanism and enables conformal coating on 3D structures. Additionally, the patent controls oxygen vacancy concentration by adjusting deposition parameters such as temperature, pressure, and precursor flow rates during the CVD process, maintaining manufacturing precision while achieving 3D structure compatibility.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If ReRAM stacks are vertically stacked to increase density, then the density of ReRAM can be increased, but the oxygen vacancy concentration control becomes more difficult

Engineering Contradiction:

ImproveReRAM densityVSAvoidoxygen vacancy concentration control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent segments the ReRAM structure into multiple vertically stacked units, each with its own bottom electrode, metal oxide layer, and top electrode. The CVD deposition process is applied independently to each layer, allowing precise control of oxygen vacancy concentration in each segment while achieving high overall density through vertical stacking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from planar ReRAM structures to vertically stacked three-dimensional structures. By utilizing the vertical dimension for stacking multiple ReRAM units, the patent increases storage density while the CVD process ensures uniform deposition and consistent oxygen vacancy control across all vertical layers.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 allows for the creation of RRAM stacks that can be effectively integrated into three-dimensional structures, enhancing their performance and applicability in neuromorphic computing and high-density memory applications by precisely controlling oxygen vacancy concentration.

Implementation Method 1

formed from an Atomic Layer Deposition (ALD) of one or more oxides

Methodology Applied

Scientific EffectAtomic Layer Deposition:

Implementation Method 2

An oxygen vacancy concentration of the resistive switching memory stack is controlled by (i) a thickness of the plurality of metals forming the top electrode and (ii) a percentage of a particular one of the plurality of metals in the metal layer stack of the top electrode

Methodology Applied

Scientific EffectOxygen vacancy concentration control:

Data Source

PatentUS10270029B2Resistive switching memory stack for three-dimensional structure

Publication Date: 2019.04.23 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A resistive switching memory stack is provided. The resistive switching memory stack includes a bottom electrode, formed from one or more conductors. The resistive switching memory stack further includes an oxide layer, disposed over the bottom electrode, formed from an Atomic Layer Deposition (ALD) of one or more oxides. The resistive switching memory stack also includes a top electrode, disposed over the oxide layer, formed from the ALD of a plurality of metals into a metal layer stack. An oxygen vacancy concentration of the resistive switching memory stack is controlled by (i) a thickness of the plurality of metals forming the top electrode and (ii) a percentage of a particular one of the plurality of metals in the metal layer stack of the top electrode.