Josephson Junction Layout for Uniform Qubit Characteristics
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Solution Overview
Problem
Variations in characteristics among qubits in quantum operation devices lead to inconsistent coherence times, making stable quantum operations challenging.
Innovation Solution
A superconducting circuit design incorporating a Josephson device with specific manufacturing methods using vapor deposition masks to align the incident angles of evaporation substances uniformly across the substrate, ensuring consistent shapes and reducing variations among qubits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vapor deposition methods are used without aligned masks, then manufacturing process is simpler, but variations in qubit characteristics increase due to inconsistent incident angles
Solution Approach 1:
The patent introduces alignment marks as intermediary elements that mediate between the substrate and vapor deposition masks. These marks provide a reference framework that enables precise mask positioning, thereby ensuring consistent incident angles across all qubits without requiring complex direct measurement or adjustment systems.
Solution Approach 2:
The patent implements preliminary alignment mark formation on the substrate before mask deposition. By pre-establishing the alignment reference system, the incident angle consistency is ensured from the outset of the vapor deposition process, eliminating the need for post-processing adjustments or complex real-time alignment mechanisms.
2Manufacturing precision
If multiple separate deposition steps are used for different layers, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent combines multiple vapor deposition operations into a single integrated process sequence. By maintaining mask alignment and performing successive layer depositions without removing or realigning masks between steps, the system achieves both precise layer thickness control and improved manufacturing throughput through process consolidation.
Solution Approach 2:
The patent enables continuous vapor deposition operations by maintaining mask placement throughout the multi-layer formation process. The aligned masks remain in position while different materials are deposited sequentially, eliminating idle time associated with mask removal and realignment, thus sustaining continuous productive action throughout the manufacturing process.
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 method suppresses variations in qubit characteristics, enhancing stability and coherence times, and improves manufacturing throughput.
Implementation Method 1
a Z-axis direction of the substrate is parallel to a traveling direction of an evaporation substance emitted from a vapor deposition source
Data Source
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AI summary
A Josephson device includes: a first superconducting metal layer that includes a first surface; a second superconducting metal layer that includes a second surface that faces the first surface; and an insulating layer provided between the first surface and the second surface, and an outline of the second surface is inside an outline of the first surface in a plan view from a direction perpendicular to the first surface.