Single-Layer Josephson Junction Layout for Simpler Quantum Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for manufacturing Josephson junctions in superconducting quantum circuits are complex and require multiple steps, making them difficult to implement effectively.
Innovation Solution
A nonlinear element device is created using a single step evaporation of granular superconductive material as a single layer on a substrate, with a specific electrode pattern that includes a discontinuity, allowing for easy formation of a Josephson junction suitable for quantum circuits, where the electrodes are laterally displaced with a controlled contact area and dimensions larger than the superconducting coherence length to ensure nonlinearity and quantum coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double angle shadow evaporation or successive lithography steps with ion milling are used to manufacture Josephson junctions, then the manufacturing precision and reliability are improved, but the device complexity and manufacturing time increase significantly
Solution Approach 1:
The patent combines multiple separate manufacturing steps (shadow evaporation angles, lithography steps, ion milling processes) into a single evaporation step that forms the complete Josephson junction structure. The granular superconductive material is deposited in one continuous process, merging what were previously distinct fabrication operations into a unified manufacturing approach.
Solution Approach 2:
The invention uses granular superconductive material with specific grain size distributions (0.5-10 nm) to create the Josephson junction structure. The granular nature of the material allows the formation of tunnel barriers and superconducting regions through controlled deposition, segmenting the functional elements at the material level rather than requiring separate fabrication steps.
2Manufacturing precision
If multiple lithography and ion milling steps are employed to create Josephson junctions, then the contact area precision is improved, but the manufacturing time and process complexity increase
Solution Approach 1:
The granular superconductive material is prepared in advance with controlled grain size and distribution characteristics before deposition. This preliminary preparation of the material structure allows the single evaporation step to directly form the precise contact areas and tunnel barriers without requiring subsequent lithography or ion milling steps to define the geometry.
3Ease of manufacture
If a single layer evaporation method is used to form the electrode pattern, then the ease of manufacture is improved, but the manufacturing precision may be compromised
Solution Approach 1:
The invention controls the deposition parameters ( deposition rate, substrate temperature, oxygen partial pressure) to achieve the desired electrode pattern precision in a single step. By optimizing these parameters, the granular material forms with controlled grain size and distribution, achieving both manufacturing simplicity and pattern precision simultaneously.
Solution Approach 2:
The use of granular superconductive material as a composite structure (metal grains in metal oxide matrix) allows the single layer to inherently provide both the superconducting regions and the tunnel barriers. This composite material approach enables the single evaporation step to create the complete Josephson junction structure with appropriate precision.
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 simplifies the manufacturing process while maintaining high nonlinearity and quantum coherence, enabling the production of Josephson junctions that can effectively isolate energy levels and preserve quantum coherence over extended timescales.
Implementation Method 1
the electrode pattern is formed by a single step evaporation of a granular superconductive material as a single layer
Implementation Method 2
a single step evaporation of a granular superconductive material as a single layer
Data Source
Figure 1~2
Figure 3(a)~3(d)
Figure 4~5
AI summary
The present invention relates to a nonlinear element device, a circuit comprising the nonlinear element device, use of the circuit as a quantum circuit, a method of producing a nonlinear element device and a method of producing a circuit.