Vertical Transmon Qubit Structure Using TSVs for Coherence Density
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Solution Overview
Problem
Implementing quantum computing architectures in limited space is challenging due to the need for special structures and materials that address quantum phenomena like superposition and entanglement, and charge noise causes decoherence, which is difficult to shield.
Innovation Solution
A method for fabricating vertical transmon qubit structures using through-silicon-via (TSV) and superconducting materials like niobium and aluminum, with Josephson junctions and resonators, to create a resilient quantum computing architecture that suppresses electromagnetic interference and maintains coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If quantum computing architecture is implemented in limited space, then qubit density is improved, but manufacturing complexity increases due to special structures and materials required for quantum phenomena
Solution Approach 1:
The patent transitions from planar 2D qubit arrangement to vertical 3D stacking architecture. Multiple qubit layers are stacked vertically with alternating superconducting and dielectric layers, enabling higher qubit density within limited footprint by utilizing the third dimension (vertical direction) for spatial arrangement.
Solution Approach 2:
The patent implements nested structures where through-silicon vias (TSVs) are embedded within the vertical stack, and qubit elements are nested within alternating superconducting and dielectric layers. The TSVs penetrate through multiple layers to provide vertical interconnects, creating a compact nested architecture that maximizes space utilization.
2Reliability
If special structures and materials are used to address quantum phenomena, then quantum coherence is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs specific material parameters and dimensional control to achieve quantum coherence. The superconducting layers (niobium, aluminum) are deposited with controlled thicknesses (e.g., 5-10 nm), and dielectric layers are precisely formed to create appropriate capacitance values. These parameter optimizations ensure quantum coherence while maintaining manufacturability through standard thin-film deposition techniques.
Solution Approach 2:
The patent uses composite material structures combining superconducting materials (niobium, aluminum, titanium nitride) with dielectric materials (silicon dioxide, silicon nitride, aluminum oxide) in alternating layers. This composite architecture provides both the superconductivity needed for quantum coherence and the dielectric properties required for qubit operation, while being compatible with existing semiconductor fabrication processes.
3Reliability
If charge noise shielding is implemented, then decoherence is reduced, but device complexity increases
Solution Approach 1:
The patent introduces dielectric layers as intermediary materials between superconducting layers. These dielectric layers (silicon dioxide, silicon nitride, aluminum oxide) act as mediators that electrically isolate adjacent superconducting layers, reducing direct coupling and minimizing charge noise effects. This intermediary approach provides shielding without requiring complex additional structures.
Solution Approach 2:
The patent applies different material properties at different locations within the vertical stack. Superconducting layers provide electromagnetic shielding and charge isolation at specific interfaces, while dielectric layers provide electrical insulation in other regions. This localized functional assignment achieves noise shielding through the inherent properties of materials at specific positions rather than through global complex shielding structures.
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 vertical transmon qubit structures enhance qubit density and coherence, enabling efficient quantum computing by reducing decoherence from charge noise and environmental interference.
Implementation Method 1
A first electrode of a Josephson junction (JJ) is located on a portion of the first surface of the substrate and adjacent to the TSV. A second electrode of the JJ is in contact with the TSV and on a second portion of the first surface of the substrate.
Implementation Method 2
A through silicon via (TSV) is created in the center portion of the substrate by way of etching the substrate in the center portion of the substrate.
Implementation Method 3
A first layer of aluminum (Al) is provided on the bottom surface the substrate. A first layer of niobium (Nb) is on a bottom side of the substrate. A second layer of Al is deposited within the TSV. A second layer of Nb is deposited on a top side of the substrate.
Data Source
AI summary
A vertical transmon qubit structure, includes a substrate having a first surface and a second surface. A through-silicon-via (TSV) is located in the substrate. A first electrode of a Josephson junction (JJ) is located on a portion of the first surface of the substrate and adjacent to the TSV. A second electrode of the JJ is in contact with the TSV and on a second portion of the first surface of the substrate. The first electrode is separated from the second electrode by an insulator.