Vertical Stack Memory Device Oxygen Scavenger Layers
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Solution Overview
Problem
Current semiconductor memory devices, particularly vertical NAND (VNAND) products, face challenges in scaling unit cells and reducing operating voltage, which limits integration density and efficiency.
Innovation Solution
A memory device with a vertical stack structure that includes a plurality of memory cells, each comprising gate electrodes, a channel layer, a recording material layer, and oxygen scavenger layers. The oxygen scavenger layers, made of non-oxide materials, form oxygen vacancies in the recording material layer, enhancing resistance change characteristics and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vertical NAND (VNAND) structure is used to increase integration density, then integration density is improved, but unit cell scaling and operating voltage reduction become limited
Solution Approach 1:
The patent transitions from planar 2D memory cell architecture to vertical 3D stack structure, where memory cells are arranged in the vertical dimension rather than spreading horizontally. This dimensional change allows continued scaling of integration density by stacking more memory cells vertically without being constrained by planar area limitations, effectively resolving the contradiction between integration density and unit cell scaling capability.
Solution Approach 2:
The patent implements a nested structure where multiple functional layers (gate electrodes, channel layers, recording material layers, oxygen scavenger layers) are stacked vertically within a compact footprint. Each layer is nested within the vertical stack, allowing high integration density while maintaining functional integrity and enabling continued scaling through additional vertical stacking.
2Reliability
If oxygen scavenger layers are introduced to form oxygen vacancies, then resistance change characteristics are improved, but device structure complexity increases
Solution Approach 1:
The oxygen scavenger layers serve multiple functions: they form oxygen vacancies in the recording material layer to enable resistance change, act as a interface layer between the insulating substrate and recording material, and provide structural organization for the vertical stack. This multi-functionality improves resistance change characteristics while minimizing the increase in device complexity by consolidating multiple roles into a single layer type.
Solution Approach 2:
The oxygen scavenger layers are pre-formed during the fabrication process before final memory operations, creating oxygen vacancies in advance within the recording material layer. This preliminary action ensures stable resistance change characteristics during operation without requiring complex real-time control mechanisms, thereby improving reliability while keeping the device structure relatively simple.
3Use of energy by moving object
If unit cell scaling is reduced to lower operating voltage, then power consumption is reduced, but integration density improvement is limited
Solution Approach 1:
The patent resolves this contradiction by moving the scaling strategy from the planar dimension to the vertical dimension. Instead of reducing unit cell size in the plane to achieve both lower voltage and higher density, the vertical stack structure allows integration density to increase through vertical stacking while unit cells can be optimized for lower operating voltage independently, thus decoupling these two parameters.
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 proposed memory device achieves stable memory operations, increased integration density, and improved reliability by effectively forming and maintaining oxygen vacancies in the recording material layer, thus enabling smoother resistance changes and enhanced data storage capabilities.
Implementation Method 1
Each of the plurality of oxygen scavenger layers comprises an element that forms oxygen vacancies in the recording material layer and does not comprise oxygen
Data Source
AI summary
Disclosed are a memory device including a vertical stack structure, a method of manufacturing the same, and/or an electronic device including the memory device. The memory device includes a plurality of memory cells. The plurality of memory cells comprise a plurality of gate electrodes, a channel layer held in common by the plurality of memory cells, a recording material layer held in common by the plurality of memory cells, and a plurality of oxygen scavenger layers separated from each other. The plurality of gate electrodes and the plurality of oxygen scavenger layers are disposed so that the plurality of gate electrodes correspond to the plurality of oxygen scavenger layers one to one. Each of the plurality of oxygen scavenger layers comprises an element that forms oxygen vacancies in the recording material layer and does not comprise oxygen.