3D Flash Memory Macaroni Layer Heat Dissipation
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Solution Overview
Problem
The integration density and reliability of two-dimensional flash memory cells are limited by short-channel effects, cell disturbances, and manufacturing costs, which are exacerbated by the low thermal conductivity of poly-crystalline silicon used in vertically-integrated 3D V-NAND flash memory cells, leading to inefficient heat dissipation and reduced performance.
Innovation Solution
A method is introduced to improve heat dissipation in vertically-integrated 3D flash memory by using a macaroni layer with high thermal conductivity, specifically forming a second macaroni layer with materials like tungsten, titanium nitride, or carbon-based materials inside a first macaroni layer, allowing effective heat dissipation to the substrate, thereby enhancing cell reliability and endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If poly-crystalline silicon is used in vertically-integrated 3D V-NAND flash memory cells to achieve high integration density, then the integration degree is improved, but the thermal conductivity is insufficient leading to poor heat dissipation and reduced reliability
Solution Approach 1:
The patent applies composite materials by combining poly-crystalline silicon with high thermal conductivity materials (such as diamond, cubic silicon carbene, or boron nitride) to form a composite structure. This composite approach allows the memory cell to maintain the electrical properties of poly-crystalline silicon while incorporating materials with superior thermal conductivity to improve heat dissipation efficiency.
Solution Approach 2:
The patent implements local quality by selectively enhancing the thermal conductivity in specific regions of the memory cell structure. High thermal conductivity materials are introduced in the macaroni layer and charge storage layer where heat accumulation is most critical, while maintaining the original poly-crystalline silicon structure in other regions where electrical functionality is prioritized.
2Productivity
If the cell size is reduced to increase the number of cells per chip, then the integration degree is improved, but short-channel effects and cell disturbances are intensified reducing reliability
Solution Approach 1:
The patent transitions from two-dimensional planar cell structures to three-dimensional vertically-integrated structures. By stacking multiple cell layers vertically, the design achieves higher cell density per chip area while maintaining larger effective channel dimensions that reduce short-channel effects. The vertical stacking allows more cells to be packed into the same footprint without proportionally reducing cell dimensions.
Solution Approach 2:
The patent employs nested structures where charge storage layers and macaroni layers are embedded within and around the channel structures. This nested arrangement allows for complex 3D configurations that maximize space utilization while maintaining proper electrical isolation and reducing interference between adjacent cells.
3Ease of manufacture
If conventional macaroni layer materials are used in vertically-integrated 3D flash memory, then the manufacturing process is simple, but the thermal conductivity is low leading to insufficient heat dissipation
Solution Approach 1:
The patent changes the thermal parameter (thermal conductivity) of the macaroni layer by introducing high thermal conductivity materials. This parameter change allows the macaroni layer to maintain its insulating electrical properties while achieving superior thermal conduction capabilities to dissipate heat from the channel and charge storage regions.
Solution Approach 2:
The high thermal conductivity macaroni layer acts as an intermediary thermal pathway between the heat-generating channel/charge storage regions and the substrate. This intermediary structure facilitates efficient heat transfer from the active cell regions to the substrate without requiring direct contact between the channel and substrate, maintaining electrical isolation while improving thermal management.
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 effectively dissipates heat generated during operation, improving cell data retention, lifespan, and reducing distortion phenomena, thus enhancing the reliability and performance of high-integration 3D flash memory cells.
Implementation Method 1
a second macaroni layer which is surrounded by the first macaroni layer and has a high thermal conductivity
Implementation Method 2
electrons injected into the charge storage layer are stored by a Fowler-Nordheim Tunneling phenomenon or a hot-carrier injection phenomenon
Implementation Method 3
electrons injected into the charge storage layer are stored by a Fowler-Nordheim Tunneling phenomenon or a hot-carrier injection phenomenon
Data Source
AI summary
Disclosed are a vertically-integrated 3-dimensional flash memory for improving a reliability of cells and a fabrication method thereof. The fabrication method of the vertically-integrated 3-dimensional flash memory includes sequentially stacking a first insulating layer and a second insulating layer on a substrate to form a plurality of insulating layers, etching a portion of the insulating layers to expose an area of the substrate, forming a channel layer on a side surface of the etched insulating layers and on the substrate, forming a first macaroni layer on the channel layer, and forming a second macaroni layer on the first macaroni layer such that a side surface and a lower surface of the second macaroni layer are surrounded by the first macaroni layer.