Silicon Quantum Dot Layout for Dense Qubit Routing
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Solution Overview
Problem
In quantum computing, routing electrodes to address qubits in dense arrays is challenging due to space constraints and high failure rates, especially in planar layouts, which complicates the scaling of quantum devices for larger qubit arrays.
Innovation Solution
A silicon-based quantum device with a metallic structure configuration that creates an elongate channel with a vertex, allowing for improved confinement and control of quantum charge carriers, enabling the fabrication of two-dimensional arrays using planar routing and providing individual control over charge carrier occupation and resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrodes are routed in planar layouts to address qubits, then qubits can be addressed individually, but qubits need to be spaced out which increases device area
Solution Approach 1:
The patent transitions from planar electrode routing to three-dimensional vertical routing using conductive vias. Electrodes extend perpendicular to the qubit array plane, allowing dense qubit packing while maintaining individual addressing capability through vertical wire routing that passes through or near each qubit location.
Solution Approach 2:
The patent implements a hierarchical structure where conductive vias are positioned within or adjacent to each qubit unit cell. The electrode routing is nested within the vertical dimension of the device structure, with multiple electrode layers potentially stacked vertically to address different qubit types or functions within the same planar footprint.
2Area of stationary object
If vertical routing using conductive vias is implemented, then device area is reduced, but processing complexity and failure rate increase
Solution Approach 1:
The patent combines the formation of conductive vias with existing semiconductor fabrication processes. The vertical electrodes are integrated into the same processing flow as transistor fabrication, using similar deposition, etching, and planarization techniques. This merging of routing fabrication with device fabrication reduces overall processing complexity despite the added three-dimensional routing capability.
3Ease of manufacture
If qubits are spaced out in planar layouts, then electrode routing is simplified, but qubit density decreases
Solution Approach 1:
The patent resolves the density-routing contradiction by moving electrode routing to the vertical dimension. Qubits can be densely packed in the planar plane while electrodes extend vertically through conductive vias to provide individual addressing. This separates the qubit density optimization (planar) from the routing optimization (vertical), allowing both high density and manufacturable routing.
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 configuration enhances the scalability and control of quantum charge carriers, facilitating the creation of two-dimensional arrays while reducing manufacturing complexity and improving the confinement of quantum charge carriers, thus addressing the challenges of electrode routing in quantum computing.
Implementation Method 1
the first, second, third, fourth and fifth electric potentials are controllable to define an electrical potential well to confine quantum charge carriers in an elongate quantum dot beneath the elongate channel
Implementation Method 2
define an electrical potential well to confine quantum charge carriers
Data Source
AI summary
A silicon-based quantum device is provided. The device comprises: a first metallic structure (501); a second metallic structure (502) laterally separated from the first metallic structure; and an L-shaped elongate channel (520) defined by the separation between the first and second metallic structures; wherein the elongate channel has a vertex (505) connecting two elongate parts of the elongate channel. The device further comprises: a third metallic structure (518), mediator gate, positioned in the elongate channel; a fourth metallic structure (531) forming a first barrier gate, arranged at a first end of the third metallic structure; and a fifth metallic structure (532) forming a second barrier gate arranged at a second end of the third metallic structure. The first, second, third, fourth and fifth metallic structures are configured for connection to first, second, third, fourth and fifth electric potentials respectively. The first, second, fourth and fifth electric potentials are controllable to define an electrical potential well to confine quantum charge carriers in an elongate quantum dot beneath the elongate channel. The fourth and fifth electric potentials and the position of the fourth and fifth metallic structures define first and second ends of the elongate channel respectively. The width of the electrical potential well is defined by the position of the first and second metallic structures and their corresponding electric potentials; and the length of the electrical potential well is defined by the position of the fourth and fifth metallic structures and their corresponding electric potentials. The third electric potential is controllable to adjust quantum charge carrier energy levels in the electrical potential well.