Semiconductor Memory Shield Layer for Hydrogen Diffusion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices are scaled down, their operating characteristics deteriorate due to increased integration, leading to issues with structural stability and reliability, and there is a need for methods to enhance integration, resistance, and current drive capability while minimizing defects.
Innovation Solution
A semiconductor memory device is designed with a peripheral circuit structure and a cell array structure on a semiconductor substrate, featuring a shield layer with low hydrogen diffusivity between them, and dielectric layers with varying hydrogen concentrations to prevent hydrogen-induced damage and improve fabrication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MOSFETs are scaled down to increase integration, then integration density is improved, but operating characteristics deteriorate
Solution Approach 1:
The patent introduces vertical channel transistors that extend in the third dimension (vertical direction) rather than only in the planar direction. This dimensional change allows increased integration density while maintaining or improving operating characteristics by providing longer channel lengths and better control over current flow paths.
Solution Approach 2:
The patent employs composite material structures including multiple dielectric layers with different hydrogen concentrations and a shield layer with low hydrogen diffusivity. These composite structures protect active patterns from hydrogen damage while enabling advanced transistor designs that improve both integration and operating characteristics.
2Reliability
If hydrogen concentration is increased in dielectric layers to prevent interface defects, then reliability is improved, but hydrogen damage to active patterns occurs
Solution Approach 1:
The patent introduces a shield layer as an intermediary barrier between the high-hydrogen dielectric layers and the active patterns. This shield layer has low hydrogen diffusivity, acting as a mediator that blocks hydrogen atoms from reaching and damaging the active patterns while allowing the dielectric layers to maintain their hydrogen concentration for defect prevention.
Solution Approach 2:
The patent segments the dielectric structure into multiple layers with different hydrogen concentrations and functional roles. The first dielectric layer has high hydrogen concentration for preventing interface defects, while the second dielectric layer and shield layer have controlled hydrogen content to protect active patterns, creating a segmented approach to hydrogen management.
3Reliability
If shield layer with low hydrogen diffusivity is introduced to prevent hydrogen damage, then reliability is improved, but device complexity increases
Solution Approach 1:
The shield layer is designed to serve multiple functions simultaneously: it acts as a hydrogen barrier to protect active patterns, provides structural support as part of the dielectric stack, and can serve as an etch stop layer during fabrication. This multi-functionality reduces the need for additional separate layers, thereby limiting the increase in device complexity.
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 solution enhances structural stability and operating reliability of semiconductor memory devices by preventing hydrogen diffusion and reducing defects during fabrication and operation, thereby improving integration and performance.
Implementation Method 1
A hydrogen concentration of the first dielectric layer may be greater than a hydrogen concentration of the second dielectric layer. A hydrogen diffusivity of the shield layer may be less than a hydrogen diffusivity of the first dielectric layer and a hydrogen diffusivity 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.