Angled Sidewall Memory Cell Structures for Filament Control
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Solution Overview
Problem
Existing memory cell structures in technologies like CBRAM and RRAM exhibit variability in filament nucleation location and require higher forming voltages due to planar electrode surfaces, leading to inefficiencies in data storage and retrieval.
Innovation Solution
The memory cell structure features electrodes with angled sidewalls less than 90 degrees, where the second electrode's contact portion is angled similarly, localizing filament nucleation between a blunted peak and the electrode contact point, concentrating the electric field and reducing variability, and using a storage element with resistance variable materials like transition metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar electrode surfaces are used, then the manufacturing process is simple, but the filament nucleation location varies and higher forming voltages are required
Solution Approach 1:
The patent applies curvature by forming electrode surfaces with non-planar geometries, specifically using convex or concave surfaces instead of flat planes. This curvature concentrates the electric field at specific regions (peaks or valleys), which localizes filament nucleation to predetermined locations, thereby improving nucleation consistency without significantly complicating the manufacturing process.
2Device complexity
If planar electrode surfaces are used, then the device structure is simple, but the forming voltage is higher
Solution Approach 1:
The curved electrode surfaces concentrate electric field lines at their extremities (peaks or valleys), creating regions of high electric field intensity. This concentration effect reduces the overall voltage required to initiate filament formation, as the critical field strength is achieved at the curved surfaces with lower applied voltages compared to planar surfaces where the field is distributed uniformly.
3Stability of the object's composition
If planar electrode surfaces are used, then the electric field distribution is uniform, but the signal-to-noise ratio is reduced
Solution Approach 1:
The curved electrode surfaces create non-uniform electric field distributions with concentrated field lines at the curved extremities. This concentration effect enhances the signal strength at the filament nucleation sites, improving the signal-to-noise ratio by creating more distinct and localized electrical events compared to the diffuse field distribution of planar electrodes.
Solution Approach 2:
The patent implements local quality by creating regions of high electric field concentration at specific locations on the electrode surfaces (peaks or valleys). This localized field enhancement creates distinct nucleation sites with strong electrical signals, while other regions of the electrode maintain different field characteristics, thereby improving overall device reliability through enhanced signal differentiation.
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 stabilizes filament nucleation, reduces forming voltage requirements, and enhances signal-to-noise ratio by increasing the contact surface area between electrodes and storage elements, improving data storage efficiency.
Implementation Method 1
localizing filament nucleation between a blunted peak of the first electrode and a point of the electrode contact portion of the second electrode, concentrating the electric field
Implementation Method 2
a storage element with resistance variable materials like transition metal oxides
Data Source
AI summary
The present disclosure includes memory cell structures and method of forming the same. One such memory cell includes a first electrode having sidewalls angled less than 90 degrees in relation to a bottom surface of the first electrode, a second electrode, including an electrode contact portion of the second electrode, having sidewalls angled less than 90 degrees in relation to the bottom surface of the first electrode, wherein the second electrode is over the first electrode, and a storage element between the first electrode and the electrode contact portion of the second electrode.