Vertical Nonvolatile Memory With Selective Diode
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Solution Overview
Problem
Current nonvolatile memory devices, such as ReRAMs with cross-bar arrays, face limitations in integration and are prone to reading errors, necessitating the development of more integrated and error-reduced memory solutions.
Innovation Solution
A vertical nonvolatile memory device is designed with a selective diode, featuring a conductor-insulator horizontal structure, a memory layer, a complex conductor-insulator structure, and a conductor-insulator vertical structure, where the selective diode is strategically placed to enhance integration and reduce reading errors, utilizing alternately stacked conductive and insulating layers and materials like transition metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ReRAMs with cross-bar arrays are used, then integration is improved, but reading errors increase
Solution Approach 1:
The memory device is segmented into distinct functional regions: a conductor-insulator horizontal structure, a memory layer, a complex conductor-insulator structure, and a conductor-insulator vertical structure. This segmentation allows separate optimization of integration (through compact horizontal stacking) and reliability (through the selective diode in the vertical structure that prevents reading errors by controlling current flow paths).
Solution Approach 2:
The selective diode acts as an intermediary component between the memory layer and the external circuitry. It mediates the read operation by allowing current to flow only in the correct direction, thereby preventing false readings while maintaining the high integration benefits of the cross-bar array architecture.
2Reliability
If horizontal ReRAM structures are used, then reading errors are reduced, but integration is limited
Solution Approach 1:
The invention transitions from purely horizontal cross-bar arrays to a three-dimensional structure by adding vertical conductor-insulator structures. This dimensional change allows the selective diode to be integrated vertically above the horizontal memory elements, achieving both high integration density and improved reliability through error prevention mechanisms.
Solution Approach 2:
The structure employs nested arrangements where the conductor-insulator horizontal structure contains memory elements, which are then nested within a larger complex conductor-insulator structure, and finally integrated into the vertical conductor-insulator structure. This nesting achieves high integration while incorporating selective diodes for reliability.
3Reliability
If selective diodes are added to prevent reading errors, then reliability is improved, but device complexity increases
Solution Approach 1:
The selective diode functionality is merged with the existing conductor-insulator structures. Rather than adding completely separate diode components, the invention integrates rectifying functionality into the conductor-insulator vertical structure, combining memory storage and error prevention functions into a unified structure that reduces overall device complexity.
Solution Approach 2:
The conductor-insulator structures serve multiple functions: they provide structural support, enable electrical connectivity, and incorporate selective diode functionality for error prevention. This multi-functionality reduces the need for separate components, thereby improving reliability without proportionally increasing device 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 vertical nonvolatile memory device achieves higher integration and reduces reading errors, enabling efficient data recording and retrieval with less power consumption.
Implementation Method 1
the selective diodes 130 allow forward currents but block most of reverse currents so that reading errors can be prevented
Implementation Method 2
The memory devices 140 include resistance layers so that information can be recorded in the memory devices 140
Data Source
AI summary
Provided are a vertical nonvolatile memory device and a method for fabricating the vertical nonvolatile memory device. The vertical nonvolatile memory device can be integrated more highly as compared with a nonvolatile memory device of the related art. In addition, since the vertical nonvolatile memory device includes a selective diode, reading errors can be prevented.