Superconducting Junction Layout Without Resist Residue
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Solution Overview
Problem
The lithography processes used to create superconducting junctions often leave polymer residues on interfaces and substrates, which can impair the function of superconducting devices by introducing two-level-systems.
Innovation Solution
A method involving angle evaporation to form superconducting junctions and capacitive elements within a recessed pattern in a superconducting layer without the need for resists, using a stencil mask to deposit junction layers on the sidewalls and bottom of a trench, with oxidation forming an insulating layer to improve junction quality and integration with capacitive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithography processes are used to create hollow structures for superconducting junctions, then junction formation is achieved, but polymer residues are left on interfaces and substrate which impair junction function
Solution Approach 1:
The patent removes the resist material entirely from the process by using direct angle evaporation through a stencil mask to define the hollow structure. This extracts the harmful polymer residues from the system while maintaining the necessary geometric definition for junction formation.
Solution Approach 2:
The stencil mask serves as an intermediary tool that defines the hollow structure geometry without requiring lithographic resists. The mask allows precise deposition of superconducting materials at specific angles to create the junction geometry while leaving no organic residues on the substrate.
2Ease of manufacture
If angle evaporation with hollow structure is used, then superconducting junctions can be formed, but additional lithography is needed for adjacent circuitry which increases process complexity
Solution Approach 1:
The stencil mask approach provides multi-functionality by simultaneously defining both the hollow structure for junction formation and the patterns for adjacent circuitry in a single process step, eliminating the need for multiple sequential lithography operations.
Solution Approach 2:
The patent merges the hollow structure definition and adjacent circuitry patterning into a single angle evaporation process using the stencil mask, combining multiple functions into one operation to reduce overall process complexity.
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 reliable formation of high-quality superconducting junctions that can be easily integrated with capacitive elements, reducing the impact of polymer residues and enhancing device performance.
Implementation Method 1
performing a first angle evaporation through the stencil mask, where a first junction layer is deposited on a first sidewall of the cavity and on the cavity bottom
Implementation Method 2
performing an oxidation step where the first junction layer is oxidized to form a first insulating layer on the surface of the first junction layer
Data Source
AI summary
This disclosure describes a superconducting device comprising a trench and a cavity that extends through a superconducting base layer. The trench crosses the cavity. The superconducting device further comprises a first junction layer that extends from a first region of the superconducting base layer to the cavity, an insulating layer on the surface of the first junction layer, and a second junction layer that extends from a second region of the superconducting base layer to the cavity. The second junction layer overlaps with the insulating layer on the bottom of the cavity. The disclosure also describes a method for producing this disclosed superconducting device.