RRAM Bottom Electrode Corner Tip Design for Resistance Variability

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Solution Overview

Problem

Resistive random access memory (RRAM) devices exhibit significant resistance variability due to random formation of conducting filaments and incomplete rupture, leading to inconsistent performance across switching cycles.

Innovation Solution

The design includes bottom electrodes with corner tips angled less than ninety degrees, which helps confine and enhance the formation of conductive filaments, reducing resistance variability and improving electric field distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bottom electrodes with right-angled corners are used, then the device structure is simple and easy to manufacture, but the conducting filaments form randomly leading to high resistance variability

Engineering Contradiction:

Improveresistance distributionVSAvoidelectrode structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bottom electrode is designed with asymmetric corner tips having angles less than 90 degrees, creating a non-uniform electric field distribution that guides and confines conducting filament formation to specific regions, thereby reducing resistance variability while maintaining manufacturing feasibility through standard lithographic processes

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The corner tips of the bottom electrode are engineered with specific geometric properties (angles less than 90 degrees) to create localized high electric field regions, ensuring that conducting filaments form preferentially at these designated locations rather than randomly throughout the switching material, thus improving resistance control

Inventive Principle:

Principle #3Local quality

2Reliability

If the corner tip angle is reduced below ninety degrees, then conducting filament formation is better confined and resistance variability decreases, but fabrication precision requirements increase

Engineering Contradiction:

Improveread current variabilityVSAvoidcorner tip angle control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The corner tip angle is optimized to a specific range (less than 90 degrees) to achieve the desired balance between filament confinement and fabrication feasibility, transforming the geometric parameter to improve device reliability while remaining compatible with existing manufacturing capabilities

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 distribution and read current variability, enhancing the reliability and consistency of RRAM devices by better confining and controlling the formation of conductive filaments.

Implementation Method 1

an angle of each of the at least one corner tip may be less than ninety degrees... helps confine and enhance the formation of conductive filaments, reducing resistance variability and improving electric field distribution

Methodology Applied

Scientific EffectElectric field enhancement and confinement: Electric Field

Data Source

PatentUS11600664B2Memory devices and methods of forming memory devices

Publication Date: 2023.03.07 GLOBALFOUNDRIES SINGAPORE PTE LTD

AI summary

A memory device may be provided, including a substrate; one or more bottom electrodes arranged over the substrate; one or more switching layers arranged over the one or more bottom electrodes; and a plurality of top electrodes arranged over the one or more switching layers. Each of the one or more bottom electrodes may include at least one corner tip facing the switching layer, and an angle of each of the at least one corner tip may be less than ninety degrees.