RRAM Variable Resistance Layer Wrap-Around Filament Formation
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Solution Overview
Problem
Resistive random-access memory (RRAM) cells often have an insufficient number of conductive filaments in the variable resistance layer, leading to inadequate electric current in the low resistance state (LRS), which limits their performance.
Innovation Solution
A resistive random-access memory device is fabricated with a dielectric layer, a first electrode, and a second electrode, where the variable resistance layer is formed on the top surface and sidewall of the first electrode, and between the electrodes, allowing for the formation of multiple conductive filaments, enhancing the electric current in the LRS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional RRAM structure with limited variable resistance layer configuration is used, then the device structure is simple, but the number of conductive filaments is insufficient leading to inadequate electric current in LRS
Solution Approach 1:
The variable resistance layer is configured to wrap around the first electrode in a three-dimensional arrangement, extending from the top surface down the sidewall. This spatial extension into multiple dimensions increases the available volume and surface area for conductive filament formation, thereby increasing the number of filaments without significantly complicating the fabrication process
Solution Approach 2:
The variable resistance layer is formed with a porous or wrap-around structure that provides multiple pathways and interfaces for conductive filament formation. This structure increases the effective surface area and volume where filaments can nucleate and grow, enhancing the total number of conductive filaments in the device
2Quantity of substance
If the variable resistance layer has limited configuration, then the fabrication process is simple, but the electric current amount in LRS is insufficient
Solution Approach 1:
The variable resistance layer extends in multiple dimensions by wrapping around the first electrode's sidewall, creating additional spatial regions for electrical conduction. This dimensional expansion provides more pathways for charge carriers, increasing the total electric current in LRS while using standard thin-film deposition techniques
Solution Approach 2:
The variable resistance layer is effectively segmented into multiple regions: a top surface portion and a sidewall portion wrapping around the first electrode. Each segment can independently contribute to conductive filament formation, and the segmentation is achieved through conformal deposition processes that naturally create distinct spatial zones
3Productivity
If a conventional electrode configuration is used, then the device structure is simple, but the operational efficiency is limited due to insufficient conductive pathways
Solution Approach 1:
The first electrode is configured as a columnar structure with the variable resistance layer wrapping around its sidewall, creating a three-dimensional electrode configuration. This spatial arrangement provides multiple parallel conduction pathways radiating from the first electrode, increasing operational efficiency by enabling simultaneous current flow through multiple conductive filaments
Solution Approach 2:
The wrap-around variable resistance layer creates a porous or multi-channeled structure around the first electrode, providing numerous interconnected pathways for electrical conduction. This increases the effective conduction cross-section and enables higher current densities, improving operational efficiency
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 increased number of conductive filaments in the variable resistance layer improves the electric current amount in the LRS, enhancing the operational efficiency of the RRAM cell.
Implementation Method 1
During SET operation of a resistive random-access memory cell, a variable resistance layer between two electrodes forms conductive filaments and presents a conducting state. At this time, the variable resistance layer switches from a high resistance state (HRS) to a low resistance state (LRS).
Implementation Method 2
During RESET operation of the resistive random-access memory cell, a negative bias is applied to the resistive random-access memory, breaking the conductive filaments and presenting a non-conducting state. At this time, the variable resistance layer switches from the LRS to the HRS.
Data Source
AI summary
Provided is a resistive random-access memory device, including a dielectric layer located on a substrate, a first electrode which is a column located on the dielectric layer, a second electrode covering a top surface and a sidewall of the first electrode, and a variable resistance layer sandwiched between the top surface of the first electrode and the second electrode and between the sidewall of the first electrode and the second electrode and located between the second electrode and the dielectric layer.