Vertical Resistive Switching Device With Tunable Oxygen Vacancy Concentration
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Solution Overview
Problem
Existing 3D vertical resistive switching device (RSD) arrays face challenges in controlling oxygen vacancy concentration in metal oxides, leading to high resistivity and difficulty in scaling due to limited area for metal deposition and stoichiometric composition issues.
Innovation Solution
A fabrication method involving a 3D vertical array structure with alternating layers of dielectric material and inert metals, using atomic layer deposition for metal oxide films, and a reflow process to form a vertical electrode alloy that controls oxygen vacancy formation, combining oxygen gettering materials like aluminum with barrier metals to manage oxygen diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional metal deposition methods are used in 3D vertical RSD arrays, then fabrication is simpler, but oxygen vacancy concentration cannot be controlled leading to high resistivity
Solution Approach 1:
A barrier metal layer is introduced as an intermediary between the metal oxide film and the vertical electrode. This barrier layer mediates oxygen diffusion, allowing controlled oxygen vacancy formation in the metal oxide while maintaining fabrication feasibility through standard deposition processes
Solution Approach 2:
The invention changes physical parameters including oxygen partial pressure during deposition, barrier layer thickness, and thermal processing conditions to control oxygen vacancy concentration. By adjusting these parameters, the resistivity of the metal oxide can be tuned from high to low states
2Quantity of substance
If metal oxide films are deposited in 3D vertical structures, then high density is achieved, but area for metal deposition is limited causing stoichiometric composition issues
Solution Approach 1:
The barrier metal layer is deposited beforehand to establish a controlled oxygen diffusion pathway before the vertical electrode is formed. This preliminary structure prevents uncontrolled oxygen loss during subsequent fabrication steps, maintaining stoichiometric composition even in high-density 3D vertical structures
Solution Approach 2:
The invention uses composite structures combining metal oxide films with barrier metal layers and vertical electrodes. This composite approach allows the metal oxide to maintain its stoichiometric composition while the barrier layer provides controlled oxygen diffusion, enabling high density without compromising material quality
3Reliability
If oxygen vacancy concentration is increased to reduce resistivity, then low resistivity is achieved, but uncontrolled oxygen diffusion causes reliability issues
Solution Approach 1:
The barrier metal layer acts as a mediator that enables controlled oxygen diffusion. It allows sufficient oxygen vacancy formation to achieve low resistivity while preventing uncontrolled oxygen loss, thereby maintaining device reliability through regulated oxygen transport
Solution Approach 2:
The barrier layer creates local quality differences in oxygen concentration across the device structure. By controlling oxygen diffusion locally at the barrier layer interface, the invention achieves uniform oxygen vacancy distribution in the metal oxide, ensuring reliable resistive switching behavior
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 approach enables tunable oxygen vacancy concentration in the metal oxide, achieving low resistivity and reliable resistive switching in a scalable 3D vertical RSD array, compatible with CMOS fabrication and suitable for high-density memory and neuromorphic computing applications.
Implementation Method 1
Oxygen vacancy formation in the filament region is controlled by the first conductive alloy material of the vertical electrode
Implementation Method 2
A room temperature resistance of the filament region is below about 1×10^6 ohm
Data Source
AI summary
Embodiments of the invention are directed to a vertical resistive device. A non-limiting example of the vertical resistive device includes a conductive horizontal electrode, an opening extending through the horizontal electrode, a filament region positioned within the opening and communicatively coupled to a sidewall of the horizontal electrode, and a conductive vertical electrode positioned within the opening and communicatively coupled to the filament region. The vertical electrode includes a first conductive alloy material. Oxygen vacancy formation in the filament region is controlled by the first conductive alloy material of the vertical electrode. A room temperature resistivity of the first conductive alloy material is below about 5×10−8 ohm meters and controlled by at least one of the metals that form the first conductive alloy material.