Josephson Junction Layout With Hydrogen-Trapping Barriers

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Solution Overview

Problem

Existing superconducting Josephson junctions (JJs) suffer from critical current drift over time due to hydrogen diffusion, which affects the consistent operation of devices like SQUIDs and Qubits, hindering their application in mass production.

Innovation Solution

Incorporating larger hydrogen-trapping JJs on either side of the operating JJ and employing oxidation processes to form a robust oxide barrier, which traps hydrogen and stabilizes the critical current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrogen-trapping Josephson junctions are incorporated on either side of the operating Josephson junction, then hydrogen diffusion is prevented and critical current stability is improved, but device complexity increases

Engineering Contradiction:

Improvecritical current stabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Hydrogen-trapping Josephson junctions are introduced as intermediary elements between the operating JJ and the environment. These trap junctions act as mediators that capture hydrogen atoms before they can reach and contaminate the operating JJ, thereby preventing hydrogen diffusion while maintaining the operating JJ's performance stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The device is segmented into functional zones: operating Josephson junctions for signal processing and hydrogen-trapping junctions for protection. This segmentation allows the trapping junctions to be positioned strategically around the operating junctions, creating a protective architecture that isolates the sensitive operating region from hydrogen contamination sources.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a robust oxide barrier is formed through post-junction oxidation process, then hydrogen diffusion is prevented and junction aging is mitigated, but manufacturing complexity increases

Engineering Contradiction:

Improveresistance to hydrogen diffusionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

A robust oxide barrier is formed through post-junction oxidation as a preliminary protective action before the device is deployed. This oxidation process creates a dense oxide layer that serves as a diffusion barrier, preventing hydrogen from reaching the Josephson junction interface. By performing this protective action in advance, the device gains inherent resistance to hydrogen diffusion and aging effects.

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If hydrogen-trapping junctions are used to mitigate junction aging, then operational consistency is improved, but the device structure becomes more complex

Engineering Contradiction:

Improveoperational consistencyVSAvoiddevice structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Hydrogen-trapping junctions serve as intermediary protective elements that capture hydrogen atoms in the environment before they can reach the operating Josephson junctions. This mediation prevents hydrogen-induced aging effects, maintaining the operational consistency and critical current stability of the device over time.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful effect of hydrogen diffusion, which causes junction aging and performance degradation, is converted into a beneficial protective mechanism. By introducing dedicated hydrogen-trapping junctions, the device transforms the threat of hydrogen contamination into a controlled protective system where trap junctions deliberately capture hydrogen, thereby protecting the operating junctions and improving long-term operational consistency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively mitigates hydrogen diffusion, stabilizing the critical current and enhancing the reliability of JJs for use in microwave circuits beyond academic environments.

Implementation Method 1

performing an oxidation process to provide an oxidized top surface on the plurality of superconductor bottom electrodes

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS12604673B2Josephson junction device and method of making the same

Publication Date: 2026.04.14 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A Josephson junction (JJ) device is provided. The JJ device comprises an operating JJ, a first hydrogen-trapping JJ having a first end coupled to a first end of the operating JJ and a second end coupled to a first superconductor wire, and a second hydrogen-trapping JJ having a first end coupled to a second end of the operating JJ and a second end coupled to a second superconductor wire. The first hydrogen-trapping JJ and the second hydrogen-trapping JJ mitigates hydrogen diffusion into the operating JJ.