Non-oxide Dielectrics for Superconductor Oxygen Diffusion

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Solution Overview

Problem

The mass production of superconducting devices is hindered by the sensitivity of superconducting materials to oxygen incorporation, which is exacerbated by CMOS processing temperatures, leading to oxygen diffusion from traditional oxide-based dielectrics, affecting the integrity of superconducting properties.

Innovation Solution

Employing a non-oxide based dielectric layer with a dielectric constant of less than 6, such as amorphous silicon carbide, to mitigate oxygen diffusion, combined with photoresist patterning and etching techniques to form superconducting contacts, allowing for the fabrication of superconducting devices that maintain their properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional oxide-based dielectric materials (such as SiO2) are used in CMOS processing for superconducting devices, then the dielectric provides adequate electrical insulation, but oxygen diffusion occurs into the superconductor at processing temperatures (e.g., 400°C), degrading superconducting properties

Engineering Contradiction:
Improvesuperconducting property integrityVSAvoidoxygen diffusion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes oxygen-containing oxide materials from the dielectric layer and replaces them with non-oxide based dielectric materials. This extraction of the harmful oxygen component eliminates the source of oxygen diffusion while maintaining the essential dielectric function of electrical insulation between superconducting layers.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs non-oxide based dielectric materials that create an inert environment for the superconducting structures. These materials do not contain oxygen that could diffuse into the superconductor, effectively providing a protective atmosphere that preserves superconducting properties during CMOS processing at elevated temperatures.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If non-oxide based dielectric materials with dielectric constant less than 6 are used, then oxygen diffusion is prevented and superconducting properties are maintained, but the dielectric constant is reduced compared to traditional SiO2

Engineering Contradiction:
Improvesuperconducting property stabilityVSAvoiddielectric constant
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the material composition parameter from oxide-based to non-oxide based dielectrics, which inherently alters the dielectric constant. This parameter change is accepted as a trade-off to eliminate oxygen diffusion, and the patent specifies selecting non-oxide materials with dielectric constants less than 6 that still provide adequate electrical insulation for superconducting device operation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If photoresist patterning and etching processes are used to form superconducting contacts, then precise contact alignment and formation are achieved, but additional processing steps and time are required

Engineering Contradiction:
Improvecontact alignment precisionVSAvoidfabrication speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies photoresist material to the surface before etching the non-oxide dielectric layer to form contact holes. This preliminary patterning action defines the precise locations of superconducting contacts before the etching process, ensuring accurate alignment with underlying superconducting features while enabling subsequent rapid fabrication steps.

Inventive Principle:
Principle #10Preliminary action

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 the consistent and rapid fabrication of superconducting devices by preventing oxygen-induced degradation of superconducting materials, facilitating the mass production of superconducting devices with improved performance and reliability.

Implementation Method 1

Recent data indicates oxygen diffusion into the superconductor is strongly dependent on temperature and typical CMOS processing temperatures (e.g., 400oC) can result in oxygen diffusion from dielectrics that contain oxygen

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

irradiating and developing the photoresist material layer to form a via pattern in the photoresist material layer

Methodology Applied
Scientific EffectPhotolithography: Photography

Implementation Method 3

etching the non-oxide based dielectric layer to form openings in the non-oxide based dielectric layer based on the via pattern

Methodology Applied
Scientific EffectEtching:

Implementation Method 4

filling the openings in the non-oxide based dielectric layer with a superconducting material to form a set of superconducting contacts

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP3387681B1Non-oxide based dielectrics for superconductor devices
Publication Date: 2021.12.01 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3387681B1 patent drawingFigure 1~2
  • EP3387681B1 patent drawingFigure 3~4
  • EP3387681B1 patent drawingFigure 5~6

AI summary

A method of forming a superconductor device (50) is provided. The method includes depositing a non-oxide based dielectric layer (56) over a substrate (52), depositing a photoresist material layer (58) over the non-oxide based dielectric layer, irradiating and developing the photoresist material layer to form a via pattern in the photoresist material layer, and etching the non-oxide based dielectric layer to form openings (60) in the non-oxide based dielectric layer based on the via pattern. The method further comprises stripping the photoresist material layer, and filling the openings in the non-oxide based dielectric with a superconducting material (70) to form a set of superconducting contacts (72).