Josephson Junction Vertical Architecture for Critical Current
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Solution Overview
Problem
As technology nodes shrink, the critical current of Josephson junctions (JJs) in superconducting devices falls below acceptable thresholds, posing a challenge for maintaining sufficient noise margins in Single Flux Quantum (SFQ) technology, which relies on JJ pulse widths and logic state transmission.
Innovation Solution
The JJ structure is extended vertically away from the silicon wafer surface, maintaining a larger cross-sectional area and thus a higher critical current, even at smaller technology nodes, by using a non-superconducting structure with superconducting materials disposed both inside and around it, ensuring the JJ's critical current remains above a desired threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the JJ structure is shrunk to smaller technology nodes, then the device size is reduced, but the critical current falls below acceptable thresholds
Solution Approach 1:
The patent extends the Josephson junction structure vertically away from the silicon wafer surface, transitioning from a planar two-dimensional layout to a three-dimensional vertical architecture. This dimensional change allows the critical current to be maintained by increasing the vertical extent of the superconducting structures, compensating for the reduced lateral dimensions at smaller technology nodes
Solution Approach 2:
The patent employs a nested structure where superconducting structures are disposed both inside hollow regions of non-superconducting structures and around them externally. This nested arrangement maximizes the superconducting material volume within the constrained lateral footprint, maintaining sufficient critical current while achieving compact device sizing
2Reliability
If the JJ structure is extended vertically, then the critical current is maintained, but the device complexity increases
Solution Approach 1:
The patent divides the Josephson junction structure into distinct functional segments: non-superconducting structures with hollow regions, superconducting structures inside the hollow regions, and superconducting structures around the non-superconducting structures. This segmentation allows each component to be optimized independently while maintaining overall critical current through the combined vertical architecture
Solution Approach 2:
The non-superconducting structures with hollow regions serve multiple functions: they provide structural support, define the vertical architecture, and create cavities for positioning superconducting structures. This multi-functionality reduces the need for separate components, thereby managing complexity while achieving the vertical extension needed for maintained critical current
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 allows for reduced feature sizes in JJ circuits while maintaining a sufficient noise margin, enabling SFQ technology to support future computing and storage demands by ensuring the critical current remains greater than desired values.
Implementation Method 1
a first superconducting structure disposed inside the hollow region of the non-superconducting structure, and a second superconducting structure disposed around the non-superconducting structure outside the hollow region
Implementation Method 2
SFQ technology, which relies on the quantum mechanical quantization of magnetic flux, is a technology that may help meet future computing and storage demands. SFQ technology is based on flux storage and transmission, and uses pulses emitted by JJs.
Data Source
AI summary
Josephson junction (JJ) structures are disclosed. In some embodiments, a JJ structure may include a non-superconducting structure having a hollow region. A first superconducting structure may be disposed inside the hollow region of the non-superconducting structure, and a second superconducting structure may be disposed around the non-superconducting structure outside the hollow region.