3D Memory Stack MoB Barrier Against Oxygen Diffusion
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Solution Overview
Problem
Oxygen diffusion from molybdenum layers in three-dimensional nonvolatile semiconductor memory devices leads to degradation of the pillar structure and reduced data retention characteristics, compromising the reliability of the memory device.
Innovation Solution
Incorporating an intermediate layer of molybdenum boride (MoB) between the conductive layers and the pillar structures to suppress oxygen diffusion and prevent oxide formation, thereby enhancing the reliability of the semiconductor memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molybdenum conductive layers are used in the stacked body, then electrical conductivity is improved, but oxygen diffusion occurs from the Mo layers to the pillar structure causing degradation
Solution Approach 1:
An intermediate layer is introduced between the molybdenum conductive layer and the pillar structure to act as a diffusion barrier. This intermediate layer prevents oxygen from diffusing from the Mo layer to the pillar structure, thereby eliminating the harmful effect while maintaining the electrical conductivity function of the Mo layer.
Solution Approach 2:
The patent uses a composite structure consisting of molybdenum conductive layer combined with an intermediate barrier layer. This composite material approach allows the system to simultaneously achieve high electrical conductivity from the Mo layer and oxygen diffusion prevention from the intermediate layer.
2Quantity of substance
If multiple conductive layers are stacked to form three-dimensional memory structure, then memory capacity is improved, but oxygen diffusion leads to degradation of pillar structure
Solution Approach 1:
The patent segments the three-dimensional stacked structure into distinct functional layers separated by intermediate barrier layers. Each conductive layer is isolated from the pillar structure by its own intermediate layer, preventing oxygen diffusion while maintaining the high-capacity stacked configuration.
Solution Approach 2:
Intermediate layers are positioned between each conductive layer and the pillar structure to serve as protective mediators. These intermediate layers prevent oxygen from reaching the pillar structure while allowing the multi-layer stacking to proceed for increased memory capacity.
3Device complexity
If conventional structure without intermediate layer is used, then device complexity is reduced, but oxide formation occurs on conductive layers
Solution Approach 1:
An intermediate layer is introduced as a thin barrier between the conductive layer and the environment/pillar structure. This intermediate layer prevents oxide formation on the conductive layer surface while adding minimal structural complexity to the overall device.
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 MoB intermediate layer effectively prevents oxygen diffusion, maintaining the integrity of the block insulating layer and improving data retention characteristics, thus enhancing the overall reliability of the semiconductor memory device.
Implementation Method 1
Oxygen diffusion from molybdenum layers in three-dimensional nonvolatile semiconductor memory devices leads to degradation of the pillar structure and reduced data retention characteristics
Data Source
AI summary
According to one embodiment, a semiconductor memory device includes a stacked body in which a plurality of conductive layers containing molybdenum (Mo) are stacked to be spaced apart from each other in a first direction, a pillar structure including a semiconductor layer extending in the first direction in the stacked body, a partition structure extending in the first direction and in a second direction intersecting the first direction in the stacked body, and dividing the stacked body in a third direction intersecting the first and second directions, and a plurality of intermediate layers, each including a portion provided between the pillar structure and a corresponding one of the conductive layers, and containing a compound of molybdenum (Mo) and boron (B).