Vertical ReRAM with Embedded Selectors for Leakage Control
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Solution Overview
Problem
In 3D arrays of resistive switching memory devices, leakage paths through unselected devices, known as sneak paths, are difficult to shut off due to the challenges in implementing selector devices, which is essential for increasing memory density and preventing unauthorized current flow.
Innovation Solution
A vertical resistive switching memory device is designed with a selector device encapsulating a portion of the ReRAM stack in an undercut region adjacent to recessed electrode material layers, forming a material stack of alternating interlayer dielectric and electrode materials, allowing for individual selection of ReRAM devices without area penalty and preventing leakage paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If vertically stacking ReRAM stacks is implemented to increase memory density, then memory density is improved, but leakage paths through unselected devices (sneak paths) are generated
Solution Approach 1:
The patent divides the ReRAM stack into multiple segments by inserting selector devices at different heights within the stack. Each selector device segments the conduction path, preventing continuous leakage paths through unselected devices while maintaining the vertical stacking architecture for high density.
Solution Approach 2:
Selector devices are introduced as intermediary elements within the ReRAM stack. These selectors act as mediators that control and block sneak paths by selectively shutting off conduction paths through unselected devices, enabling individual device selection in the 3D array.
2Object-generated harmful factors
If selector devices are added to shut off sneak paths, then leakage paths are prevented, but device complexity increases
Solution Approach 1:
The patent incorporates selector devices in the vertical dimension within the ReRAM stack rather than adding them in the lateral plane. This vertical integration approach prevents sneak paths without increasing the lateral footprint or overall device complexity, as the selectors are embedded within the existing stack structure.
3Object-generated harmful factors
If selector devices are implemented in 3D ReRAM configurations, then sneak paths are shut off, but manufacturing difficulty increases
Solution Approach 1:
The selector devices are formed within the ReRAM stack structure during the manufacturing process, utilizing preliminary patterning and deposition steps that integrate selector formation with the existing ReRAM fabrication flow. This preliminary integration reduces subsequent manufacturing complexity.
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 embedded selector devices effectively isolate adjacent memory devices, enabling individual selection and preventing leakage, thus enhancing the density and efficiency of the memory array while maintaining area efficiency.
Implementation Method 1
Resistive random access memory (ReRAM) is considered as a promising technology for electronic synapse devices or memristors for neuromorphic computing as well as high-density and high-speed non-volatile memory applications. ReRAM is a type of non-volatile random access memory that works by changing the resistance across a dielectric solid-state material.
Data Source
AI summary
A vertical resistive switching memory device is provided that includes a resistive random access memory (ReRAM) stack embedded in a material stack of alternating layers of an interlayer dielectric material and a recessed electrode material. A selector device encapsulates a portion of the ReRAM stack and is present in an undercut region that is laterally adjacent to each of the recessed electrode material layers of the material stack.