RRAM Electrode Segmentation for Leakage Reduction
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Solution Overview
Problem
Resistive random access memory (RRAM) faces challenges with a narrow switching window and leakage issues due to the formation of conductive filaments at the edges of the switching layer, which affects reliability and endurance.
Innovation Solution
Incorporating a second bottom electrode with a higher work function and conductivity, positioned between the edges of a first bottom electrode, concentrates the electrical field at the center of the switching layer, facilitating the formation of conductive filaments away from the edges, thereby increasing the switching window and reducing forming voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bottom electrode is used in RRAM, then the device structure is simple, but the switching window is narrow and leakage occurs due to edge filament formation
Solution Approach 1:
The bottom electrode is segmented into two distinct electrodes: a first bottom electrode and a second bottom electrode. The second bottom electrode is positioned between the edges of the first bottom electrode and has different material composition (higher work function and conductivity). This segmentation allows the device to maintain simple overall structure while improving reliability by preventing edge filament formation through the presence of the second electrode with different electrical properties.
2Reliability
If the second bottom electrode with higher work function and conductivity is added, then the switching window increases and leakage reduces, but the device complexity increases
Solution Approach 1:
The second bottom electrode is strategically positioned only in the central region between the edges of the first bottom electrode, rather than uniformly across the entire device. This local quality approach allows the higher work function and conductivity materials to be applied only where needed to concentrate the electric field and prevent edge filament formation, thereby improving reliability without unnecessarily increasing overall device complexity.
3Productivity
If voltage is applied to form conductive filaments at the edges, then switching occurs, but leakage increases and switching window narrows
Solution Approach 1:
The invention converts the harmful effect of edge filament formation into a beneficial outcome. By introducing the second bottom electrode with higher work function and conductivity in the central region, the electric field is redistributed to concentrate at the center rather than at the edges. This prevents the harmful leakage associated with edge filaments while maintaining effective switching operation through controlled central filament formation.
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 the switching window and reduces leakage, improving the reliability and endurance of RRAM devices by concentrating the electric field at the center of the switching layer, thus reducing the likelihood of filament formation at the edges.
Implementation Method 1
concentrates the electrical field at the center of the switching layer
Data Source
AI summary
A semiconductor device includes a first bottom electrode, a second bottom electrode, a switching layer and a top electrode. The first bottom electrode has two edges opposite to each other, and an upper surface. The second bottom electrode is between the edges of the first bottom electrode and exposed from the upper surface of the first bottom electrode. The switching layer is over the first bottom electrode and the second bottom electrode. The top electrode is over the switching layer.