Vertical Memory Cell Structure With Shielded Hydrogen Diffusion
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Solution Overview
Problem
The scaling down of MOSFETs in semiconductor devices leads to deteriorated operating characteristics, necessitating improved integration, resistance, and current drive capability, while existing methods fail to ensure structural stability and operating reliability with reduced defects.
Innovation Solution
A semiconductor memory device design incorporating vertical channel transistors with a shield layer and dielectric layers of varying hydrogen concentrations to enhance integration and reliability, featuring a peripheral circuit structure separated by a low-hydrogen diffusivity shield layer and hydrogen-rich dielectric layers to prevent damage to active patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOSFET sizes are scaled down to increase integration, then integration density is improved, but operating characteristics deteriorate
Solution Approach 1:
The patent transitions from planar (2D) channel transistors to vertical channel transistors, utilizing the third dimension (vertical direction) to increase integration density while maintaining or improving operating characteristics. The vertical channel structure allows for higher transistor density without the detrimental effects of continued lateral scaling.
2Productivity
If vertical channel transistors are used to increase integration, then integration density and current drive capability are improved, but structural stability and operating reliability are compromised
Solution Approach 1:
The patent introduces a shield layer positioned between the peripheral circuit structure and the cell array structure. This shield layer acts as an intermediary that prevents hydrogen diffusion from the peripheral circuits into the vertical channel transistors in the cell array, thereby maintaining structural stability and operating reliability while enabling high integration density.
3Reliability
If dielectric layers with high hydrogen concentration are used to prevent interface defects, then transistor reliability is improved, but hydrogen diffusion to active patterns causes damage
Solution Approach 1:
The shield layer serves as a hydrogen diffusion barrier, preventing hydrogen atoms from migrating from the peripheral circuit dielectric layers into the vertical channel transistors. This intermediary structure allows the peripheral circuits to have high hydrogen concentration for reliability while protecting the active patterns from hydrogen-induced damage.
Solution Approach 2:
The patent segments the semiconductor device into distinct regions: peripheral circuit structures and cell array structures, separated by the shield layer. This segmentation allows different hydrogen concentration levels in different regions, optimizing both transistor reliability in peripheral circuits and preventing hydrogen diffusion damage in the cell array.
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
The design improves structural stability and operating reliability by preventing hydrogen diffusion, reducing defects, and enhancing the performance of semiconductor memory devices.
Implementation Method 1
A hydrogen concentration of the first dielectric layer may be greater than a hydrogen concentration of the second dielectric layer
Data Source
AI summary
Disclosed are semiconductor memory devices and their fabrication methods. The semiconductor memory device comprises a peripheral circuit structure including peripheral circuits on a semiconductor substrate and a first dielectric layer on the peripheral circuits, a cell array structure on the semiconductor substrate, and a shield layer between the peripheral circuit structure and the cell array structure. The cell array structure includes bit lines, first and second active patterns on the bit lines, first word lines that extend in a second direction on the first active patterns, second word lines that extend in the second direction on the second active patterns, data storage patterns on the first and second active patterns, and a second dielectric layer on the semiconductor substrate. A hydrogen concentration of the first dielectric layer is greater than that of the second dielectric layer.