Semiconductor Memory Device With Deposition-Inhibiting Layer
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Solution Overview
Problem
The challenge in semiconductor memory devices is to enhance manufacturing ease and reliability while maintaining data retention characteristics, particularly in vertically stacked NAND flash memory where downscaling of planar structures is nearing its limits and existing technologies face challenges in manufacturing and reliability.
Innovation Solution
The solution involves a semiconductor memory device configuration with a specific structure including silicon pillars, conductive films, and insulating films, along with a manufacturing method that alternately stacks inter-layer insulating films and sacrificial films, forms trenches and recesses, and uses deposition-inhibiting layers to selectively form conductive films, ensuring high data retention and easy manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vertically stacked memory cell structure is adopted to increase integration, then storage capacity is improved, but manufacturing complexity and reliability challenges increase
Solution Approach 1:
The memory device is segmented into multiple stacked memory cell layers, each containing separated floating gate electrodes and insulating films. This segmentation allows independent formation and control of each cell layer, simplifying the manufacturing process while achieving high storage capacity through vertical stacking.
Solution Approach 2:
Different regions of the device have specialized structures: floating gate electrodes in charge retention regions, insulating films in specific positions to suppress electron injection, and conductive films in interconnect regions. This local differentiation optimizes each region's function while maintaining overall manufacturing feasibility.
2Quantity of substance
If conventional stacked type memory device is manufactured, then integration is improved, but ease of manufacture deteriorates
Solution Approach 1:
Inter-layer insulating films and sacrificial films are alternately stacked in advance before forming trenches and recesses. This preliminary stacking establishes a structured foundation that guides subsequent processing steps, making the manufacturing process more systematic and easier to control.
Solution Approach 2:
Sacrificial films serve as intermediary structures during manufacturing, enabling the formation of complex three-dimensional structures through controlled removal. These films facilitate the creation of trenches and recesses without requiring direct complex patterning, simplifying the overall manufacturing process.
3Quantity of substance
If conventional stacked type memory device is manufactured, then integration is improved, but reliability deteriorates
Solution Approach 1:
The structure converts potentially harmful electron injection into the floating gate electrode into a controlled process by positioning insulating films strategically. These films suppress unwanted electron injection while allowing necessary charge storage, transforming a reliability issue into a controlled functional feature.
Solution Approach 2:
Insulating films are positioned in advance in regions where electron injection might occur, providing protective cushioning before electrons can cause damage. This preventive structure maintains data retention characteristics by blocking harmful electron paths while preserving necessary charge storage functionality.
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
This configuration effectively suppresses electron injection into the floating gate electrode, maintaining high data retention characteristics and simplifying the manufacturing process, thereby improving the reliability and ease of production of semiconductor memory devices.
Implementation Method 1
forming a deposition-inhibiting layer in a region of an inner surface of the second recess and the slit other than an exposed surface of the second insulating film; forming a conductive film on the exposed surface of the second insulating film by performing vapor deposition
Implementation Method 2
forming a conductive film on the exposed surface of the second insulating film by performing vapor deposition using a source gas via the slit and the second recess
Data Source
AI summary
A semiconductor memory device according to an embodiment, includes a semiconductor pillar extending in a first direction, a first electrode extending in a second direction crossing the first direction, a second electrode provided between the semiconductor pillar and the first electrode, a first insulating film provided between the first electrode and the second electrode and on two first-direction sides of the first electrode, a second insulating film provided between the second electrode and the first insulating film and on two first-direction sides of the second electrode, a third insulating film provided between the second electrode and the semiconductor pillar, and a conductive film provided inside a region interposed between the first insulating film and the second insulating film.