Non-volatile Memory Device with Oxygen Reservoir Layer
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Solution Overview
Problem
Next-generation non-volatile memory devices, such as RRAM, face challenges with operation errors due to leakage current and limited operating voltage ranges, which affect the reliability and density of memory cells, especially when selection devices are used to control current direction.
Innovation Solution
A non-volatile memory device design incorporating a first oxide layer with reversible filaments and an oxygen reservoir layer that absorbs oxygen to form oxygen vacancies, allowing for a sufficient operating voltage range and minimizing signal interference between memory cells, along with a method of fabricating this device using specific layer thicknesses and heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a selection device is added to control current direction, then operation errors are reduced, but device density improvement is hindered
Solution Approach 1:
The patent extracts the oxygen reservoir function from a separate component and integrates it into the oxide layer structure itself. The oxide layer contains regions with different oxygen concentrations, creating an internal oxygen reservoir that eliminates the need for additional selection devices while maintaining reliability.
Solution Approach 2:
The oxide layer serves multiple functions: it acts as both the memory element and the oxygen reservoir. By creating regions with different oxygen vacancy concentrations within the same layer, the structure performs both storage and selection functions simultaneously, improving device density without sacrificing reliability.
2Ease of operation
If turning on/off memory cells by varying resistance is used, then current direction is controlled, but operating voltage range is severely limited
Solution Approach 1:
The patent applies local quality by creating regions with different oxygen vacancy concentrations within the oxide layer. The first region has a first oxygen vacancy concentration while the second region has a second oxygen vacancy concentration, allowing different parts of the same layer to operate at different voltage thresholds and expand the overall operating voltage range.
Solution Approach 2:
The patent changes the oxygen vacancy concentration parameter within the oxide layer to create regions with different electrical properties. By controlling oxygen vacancy concentration, the patent adjusts the resistance characteristics and operating voltage requirements of different regions, thereby expanding the usable voltage range for memory operations.
3Reliability
If oxygen reservoir layer absorbs oxygen to form oxygen vacancies, then reversible filament is formed, but fabrication complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-forming regions with different oxygen vacancy concentrations during the oxide layer deposition process. This preliminary structuring of oxygen distribution allows the reversible filament formation to occur more easily during subsequent operations, reducing overall fabrication complexity.
Solution Approach 2:
The patent uses composite material structures within the oxide layer, combining regions with different oxygen vacancy concentrations in a single layer. This composite approach achieves the complex oxygen distribution needed for reliable filament formation while using a single material system, simplifying the fabrication process compared to using multiple different materials.
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 solution enhances the reliability and integration of non-volatile memory devices by expanding the operating voltage range, reducing operation errors, and improving device density, while simplifying the fabrication process and increasing yield.
Implementation Method 1
an oxygen reservoir layer disposed between the first oxide layer and the second electrode, and absorbing oxygens of the first oxide layer to form oxygen vacancy constituting a reversible filament in the first oxide layer
Implementation Method 2
the oxygen ions of the first oxide layer move to the oxygen reservoir layer to form the reversible filament in the first oxide layer
Data Source
AI summary
The present invention relates to a non-volatile memory device and a method of fabricating the same. The non-volatile memory device according to an embodiment of the present invention comprises a first electrode; a second electrode; a first oxide layer disposed between the first electrode and the second electrode, and having a reversible filament formed therein; and an oxygen reservoir layer disposed between the first oxide layer and the second electrode, and absorbing oxygens of the first oxide layer to form oxygen vacancy constituting the reversible filament in the first oxide layer. The concentration of the oxygen vacancy may increase from the first oxide layer toward the oxygen reservoir layer.