Semiconductor Columnar Portion with Triangular Upper Cross Section
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Solution Overview
Problem
Existing three-dimensional semiconductor memory devices face challenges in maintaining consistent programming and erasing characteristics across different cross-sectional configurations of columnar portions, leading to fluctuations in Write/Erase windows and operational voltages between upper and lower memory cells.
Innovation Solution
The semiconductor device employs a columnar portion with a triangular or pseudo-triangular upper transverse cross-sectional configuration and a circular or pseudo-circular lower transverse cross-sectional configuration, optimizing the surface area and curvature to stabilize the Write/Erase windows and allow for uniform programming and erasing voltages across memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a columnar portion with uniform cross-sectional configuration is used, then manufacturing is simpler, but programming and erasing characteristics fluctuate between upper and lower memory cells
Solution Approach 1:
The columnar portion is divided into two distinct segments: an upper columnar portion with a first cross-sectional configuration and a lower columnar portion with a second cross-sectional configuration. This segmentation allows each portion to be optimized for different functions, resolving the contradiction between manufacturing simplicity and characteristic consistency by introducing controlled structural variation.
Solution Approach 2:
Different cross-sectional configurations are applied to different locations (upper vs. lower portions) of the columnar structure. The upper portion has one configuration while the lower portion has another, allowing local optimization of electrical characteristics at each location while maintaining overall structural integrity.
2Reliability
If different programming and erasing voltages are applied to upper and lower memory cells, then individual cell performance is optimized, but device complexity increases
Solution Approach 1:
The columnar portion is segmented into upper and lower portions with different cross-sectional configurations, which naturally creates different electrical characteristics. This structural segmentation allows the system to achieve different voltage requirements for upper and lower memory cells through passive geometric design rather than active control complexity.
Solution Approach 2:
The upper and lower columnar portions have asymmetric cross-sectional configurations, creating inherent differences in electrical properties. This asymmetry enables different programming and erasing voltages to be applied to upper and lower memory cells, optimizing individual cell performance while the asymmetry itself manages the complexity rather than requiring additional control mechanisms.
3Productivity
If the cross-sectional area of the columnar portion is increased, then channel capacity improves, but manufacturing precision requirements increase
Solution Approach 1:
The columnar portion is divided into upper and lower segments with different cross-sectional areas. This segmentation allows the total channel capacity to be increased through cumulative effect of both portions, while each individual portion can be manufactured within standard precision tolerances, avoiding the need for extremely high precision in a single large structure.
Solution Approach 2:
Instead of increasing channel capacity by enlarging a single uniform cross-section (which would demand higher manufacturing precision), the solution transitions to a vertical dimension approach by creating different cross-sectional configurations at different heights. This dimensional transition allows capacity increase through stacking rather than lateral expansion, reducing precision requirements.
Data Source
AI summary
A surface area of a transverse cross section of an upper portion of a columnar portion is greater than a surface area of a transverse cross section of a lower portion of the columnar portion. A configuration of the transverse cross section of the upper portion is a triangle or a pseudo-triangle having three corners, or a quadrilateral or a pseudo-quadrilateral having four corners. A configuration of the transverse cross section of the lower portion is substantially a circle. The upper portion of the columnar portion is adjacent to an upper layer portion of a stacked body including a control gate of an uppermost layer of control gates. The lower portion of the columnar portion is adjacent to a lower layer portion of the stacked body including a control gate of a lowermost layer of the control gates.