3D Memory Ground Select Gate Isolation in Stacked Electrode Arrays
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Solution Overview
Problem
Two-dimensional semiconductor memory devices face challenges in reducing the area occupied by unit memory cells, limiting the degree of integration, which is addressed by transitioning to three-dimensional (3D) semiconductor memory devices.
Innovation Solution
A 3D semiconductor memory device design featuring electrode structures with ground select gate electrodes and separation regions, where the ground select gate cutting region electrically isolates the ground select gate electrodes, enhancing the reliability and integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two-dimensional or planar semiconductor memory devices are used, then the structure is simple and manufacturing is easier, but the area occupied by unit memory cells cannot be reduced and the degree of integration cannot be improved
Solution Approach 1:
The patent transitions from two-dimensional planar memory cells to three-dimensional vertically stacked electrode structures. Multiple electrodes are stacked in the vertical direction (third direction) perpendicular to the substrate, enabling memory cells to be arranged in three dimensions. This dimensional change allows significantly higher integration density without increasing the planar area occupied by each memory cell.
2Quantity of substance
If three-dimensional semiconductor memory devices with vertically stacked electrodes are implemented, then the degree of integration is improved, but electrical isolation between adjacent ground select gate electrodes becomes more difficult
Solution Approach 1:
The patent introduces ground select gate cutting regions that segment the ground select gate electrodes into isolated sections. These cutting regions create gaps or interruptions in the ground select gate electrode structures, providing electrical isolation between adjacent electrode structures. This segmentation approach maintains the benefits of three-dimensional stacking while ensuring proper electrical isolation for reliable device operation.
Solution Approach 2:
The ground select gate cutting regions act as intermediary elements between adjacent ground select gate electrodes. These cutting regions, positioned at specific locations in the vertical stacking, serve as mediators that prevent unwanted electrical coupling between neighboring electrode structures while allowing the overall three-dimensional integrated structure to function.
3Reliability
If ground select gate cutting regions are introduced to electrically isolate ground select gate electrodes, then reliability is improved, but device structure becomes more complex
Solution Approach 1:
The ground select gate cutting regions are merged with the existing separation regions between adjacent electrode structures. By combining the isolation function with the separation structure, the patent achieves electrical isolation without adding completely separate complex components. This merging approach integrates the isolation function into the overall device architecture, reducing the incremental complexity increase.
Data Source
AI summary
A three-dimensional (3D) semiconductor memory device includes electrode structures including a plurality of electrodes stacked on a semiconductor substrate, and the electrode structures extend in a first direction and are spaced apart from each other by separation regions in a second direction perpendicular to the first direction. The 3D semiconductor memory device includes ground select gate electrodes comprising lowermost electrodes among the plurality of electrodes of the electrode structures, wherein on a level of the ground select gate electrodes, the separation regions include a first end portion, and at least one ground select gate cutting region overlaps the first end portion of the separation regions and electrically isolates the ground select gate electrodes from each other.