Semiconductor Memory Device Stacked Insulating Layers
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Solution Overview
Problem
Current semiconductor memory devices face challenges in increasing storage density while maintaining effective operating voltage and retention characteristics.
Innovation Solution
A semiconductor memory device is designed with a stacked member comprising a first layer of aluminum nitride (AlN) and a second layer of silicon nitride (SiN), where the first layer is 3 nm or less in thickness, and the second layer contacts the first layer, enhancing charge storage and retention characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the memory cell size is reduced to increase storage density, then storage density increases, but operating voltage window and retention characteristics deteriorate
Solution Approach 1:
The patent employs a composite stacked member structure consisting of multiple insulating films with different material compositions and functions. The first insulating film (high-k material like HfO2), second insulating film (AlN), and third insulating film (SiN or SiO2) are stacked to create a system where each layer contributes specific properties: the high-k film provides charge storage capacity, AlN offers high breakdown voltage and thin film capability, and SiN/SiO2 provides stability and interface quality. This composite structure enables maintaining reliable retention characteristics while supporting reduced memory cell dimensions for increased storage density.
Solution Approach 2:
The patent transitions from planar memory cell structures to three-dimensional stacked configurations by vertically stacking multiple insulating films and conductive members. The stacked member structure with multiple insulating films arranged in the vertical direction (stacking direction) allows charge storage functionality to be extended into the third dimension, thereby increasing storage density without compromising the operating voltage window and retention characteristics that would be difficult to maintain in scaled-down planar structures.
2Quantity of substance
If the insulating film thickness is reduced to increase storage density, then storage density increases, but breakdown voltage and reliability deteriorate
Solution Approach 1:
The stacked member utilizes a composite insulating film structure where the second insulating film (AlN) specifically provides high breakdown voltage characteristics, while the first insulating film (high-k material) provides charge storage capacity with sufficient thickness. By combining materials with different strength and functional properties in a stacked configuration, the system achieves both thin overall thickness for high density and high breakdown voltage for reliability.
Solution Approach 2:
Different regions of the stacked member structure are assigned different material qualities and functions: the AlN layer is positioned to provide localized high breakdown voltage and electrical strength, while the high-k insulating film region is optimized for charge storage capacity. This local differentiation of material properties within the stacked structure allows the thin film system to maintain high breakdown voltage despite reduced overall thickness.
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 achieves a larger operating voltage window and improved retention characteristics, allowing for increased storage density and stable memory operations, even in reduced memory cell sizes.
Implementation Method 1
the first layer includes aluminum and nitrogen and is provided between the first insulating film and the second insulating film. A first thickness of the first layer along a first direction is 3 nm or less. The first direction is from the first semiconductor member toward the first conductive member. The second layer contacts the first layer, includes silicon and nitrogen
Data Source
AI summary
According to one embodiment, a semiconductor memory device includes a first conductive member, a first semiconductor member, and a first stacked member provided between the first conductive member and the first semiconductor member. The first stacked member includes a first insulating film, a second insulating film provided between the first insulating film and the first semiconductor member, first and second layers. The first layer includes aluminum and nitrogen and is provided between the first and second insulating films. A first thickness of the first layer along a first direction is 3 nm or less. The first direction is from the first semiconductor member toward the first conductive member. The second layer contacts the first layer, includes silicon and nitrogen, and is provided at one of a position between the first layer and the second insulating film or a position between the first layer and the first insulating film.