Three-Terminal ReRAM Cell Structure for Short-Free Switching Control
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Solution Overview
Problem
Existing ReRAM memory devices face challenges in preventing electrical shorts and optimizing device footprint, particularly in the configuration of electrodes and dielectric layers, which affect switching layer control and stability.
Innovation Solution
A three-terminal ReRAM memory structure is designed with two bottom electrodes positioned below a switching layer and a top electrode above, incorporating an oxygen enhancement layer to manage oxygen ion movement and prevent electrical shorts, while maximizing surface area for oxygen ion exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-terminal ReRAM structure is used, then the device footprint is reduced, but electrical shorts between electrodes cannot be prevented
Solution Approach 1:
The ReRAM device is segmented into three terminals: a first bottom electrode, a second bottom electrode, and a top electrode. This segmentation allows the switching layer to be positioned between the two bottom electrodes while the top electrode is positioned above the switching layer, preventing direct electrical contact between bottom electrodes and thus preventing electrical shorts.
Solution Approach 2:
The patent introduces a vertical dimension by positioning the top electrode above the switching layer, which itself is above the two bottom electrodes. This three-dimensional arrangement separates the electrodes in the vertical direction, preventing electrical shorts that would occur in a planar two-terminal configuration.
2Area of stationary object
If the device footprint is minimized, then area efficiency is improved, but control and stability of resistance switching deteriorates
Solution Approach 1:
The patent applies local quality by introducing an oxygen enhancement layer specifically at the interface between the top electrode and switching layer. This localized modification enhances oxygen ion movement and stability precisely where needed for resistance switching, without increasing the overall device footprint.
Solution Approach 2:
The patent uses composite material structures, including the oxygen enhancement layer composed of metal oxides or oxygen-containing materials, combined with the switching layer and electrode materials. This composite structure improves resistance switching stability by facilitating oxygen ion transport while maintaining a compact device footprint.
3Reliability
If oxygen ion movement is enhanced, then resistance switching control is improved, but device complexity increases
Solution Approach 1:
The oxygen enhancement layer serves as an intermediary between the top electrode and the switching layer. It mediates oxygen ion transport, facilitating resistance switching control by providing a pathway for oxygen ions to move between the electrode and switching layer, thereby improving switching control without requiring complex external oxygen supply systems.
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 switching control and stability by preventing electrical shorts and allowing for efficient switching between resistance states, improving the performance and reliability of the memory device.
Implementation Method 1
oxygen enhancement layer, which enhances oxygen ion movement and stability
Implementation Method 2
The conductive filaments may be formed, for example, by the diffusion of a conductive species (e.g., metal ions) from one or both of the electrodes into the switching layer
Data Source
AI summary
The disclosed subject matter relates generally to memory devices and a method of forming the same. More particularly, the present disclosure relates to three terminal resistive random-access (ReRAM) memory structures having two bottom electrodes and one top electrode. The present disclosure provides a structure including a first bottom electrode having an upper surface, a second bottom electrode having an upper surface, a switching layer on the upper surface of the first electrode and the upper surface of the second electrode, an oxygen enhancement layer on the switching layer, and a top electrode on the oxygen enhancement layer, the top electrode is positioned above the first bottom electrode and the second bottom electrode.