Tapered Superconductor Connectors for Current Crowding Relief

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Solution Overview

Problem

Superconductors face current crowding issues due to geometric shapes like corners, leading to increased current density and a lower superconducting threshold, and mathematically-optimal tapered connectors are difficult to manufacture, especially for widths less than 1 micron, as they are prone to errors during e-beam and lithography processes.

Innovation Solution

The use of tapered connectors with specific slope and shape criteria, defined by equations such as Equations (1)-(7), which include non-linear and linear tapers, and elongated tapered portions, to minimize current crowding effects, while being manufacturable and adaptable to various superconducting materials and processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mathematically-optimal tapered connectors are used to minimize current crowding, then current density distribution is improved, but manufacturing precision deteriorates due to e-beam and lithography errors

Engineering Contradiction:

Improvecurrent density distributionVSAvoidconnector shape accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent modifies the taper profile parameters from mathematically-optimal (e.g., exponential or power-law curves) to linear or piecewise-linear profiles. This parameter change simplifies the manufacturing process while maintaining adequate current crowding reduction, resolving the contradiction between optimal performance and manufacturability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent accepts approximate rather than precise connector shapes, tolerating manufacturing variations that would be unacceptable for critical components. This approach prioritizes functional adequacy over manufacturing precision, allowing simpler, more robust fabrication processes.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If tapered connectors with complex non-linear shapes are used, then current crowding is minimized, but ease of manufacture deteriorates

Engineering Contradiction:

Improvecurrent crowding reductionVSAvoidconnector fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the functional form of the taper profile from complex non-linear equations to linear or simple piecewise-linear relationships. This parameter simplification makes the connectors much easier to manufacture using standard lithography and e-beam processes while retaining sufficient current crowding mitigation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent divides the connector into multiple linear segments rather than using a single complex curve. This segmentation approach approximates the optimal shape using simpler geometric elements that are easier to fabricate, balancing performance and manufacturability.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11830811B2Tapered connectors for superconductor circuits

Publication Date: 2023.11.28 PSIQUANTUM CORP

AI summary

A superconducting circuit includes a first component having a first connection point. The first connection point has a first width. The superconducting circuit includes a second component having a second connection point. The second connection point has a second width that is larger than the first width. The superconducting circuit includes a superconducting connector shaped to reduce current crowding. The superconducting connector electrically connects the first connection point and the second connection point. The superconducting connector includes a first taper positioned adjacent the first connection point and having a non-linear shape and a second taper positioned adjacent the second connection point.