Vertical Memory Cell String With Oxygen Vacancy Resistance Switching
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Solution Overview
Problem
There is a need for a nonvolatile memory device with high-density and low-power characteristics that enables random access to memory cells, particularly in the context of three-dimensional NAND structures used in neuromorphic computing platforms.
Innovation Solution
A vertical nonvolatile memory device is designed with a memory cell string that includes a dielectric film composed of a mixture of a semiconductor layer and a transition metal oxide, featuring movable oxygen vacancies to change resistance states based on voltage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a three-dimensional vertical NAND structure is used to increase storage density, then storage capacity is improved, but power consumption increases and random access capability deteriorates
Solution Approach 1:
The patent changes the physical state and electrical parameters of oxygen vacancies in the dielectric film to achieve resistance switching. By controlling the position and concentration of oxygen vacancies through voltage application, the memory device achieves low-power operation with distinct resistance states for data storage, directly addressing the power consumption issue in 3D NAND structures
Solution Approach 2:
The patent employs a composite structure combining a semiconductor layer with a dielectric film containing transition metal oxide nanoparticles. This composite material system enables oxygen vacancy formation and movement, creating resistive switching behavior that reduces power consumption while maintaining high-density storage capability in the vertical architecture
2Quantity of substance
If a three-dimensional vertical NAND structure is used to increase storage density, then storage capacity is improved, but random access capability deteriorates
Solution Approach 1:
The patent segments the memory cell structure into distinct functional layers including semiconductor layers, dielectric films with oxygen vacancies, and resistance change layers. This segmentation allows independent control of each layer through word lines and bit lines, enabling random access to specific memory cells in the 3D vertical structure without affecting other cells
Solution Approach 2:
The patent applies local quality by creating spatially varying oxygen vacancy distributions in the dielectric film. By applying voltages to specific word lines and bit lines, oxygen vacancies are localized to particular regions, enabling selective resistance changes in targeted memory cells and achieving random access capability in the vertical architecture
3Use of energy by moving object
If a dielectric film with movable oxygen vacancies is used to achieve low power consumption, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the dielectric film and resistance change layer into a unified structure where oxygen vacancies in the dielectric film directly control resistance states. This integration eliminates the need for separate control mechanisms, reducing device complexity while maintaining low-power operation through oxygen vacancy movement
Solution Approach 2:
The patent implements self-service by utilizing the inherent oxygen vacancy formation and movement properties of the dielectric film material. The material automatically forms conductive filaments through oxygen vacancy migration when voltage is applied, eliminating the need for external control circuits and reducing overall device complexity while achieving low-power resistive switching
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 device achieves high-density storage with low power consumption by utilizing oxygen vacancy movements in the dielectric film to alter resistance states, enabling efficient read, program, and erase operations.
Implementation Method 1
the dielectric film having a plurality of movable oxygen vacancies distributed therein
Data Source
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AI summary
A vertical nonvolatile memory device including a memory cell string (CS) using a resistance change material is disclosed. Each memory cell string of the nonvolatile memory device includes a semiconductor layer (522) extending in a first direction and having a first surface opposite a second surface, a plurality of gates (531) and a plurality of insulators (532) alternately arranged in the first direction and extending in a second direction perpendicular to the first direction, a gate insulating layer (521) extending in the first direction between the plurality of gates and the semiconductor layer and between the plurality of insulators and the semiconductor layer, and a dielectric film (523) extending in the first direction on the surface of the semiconductor layer and having a plurality of movable oxygen vacancies distributed therein.