Quantum Dot Matrix Grid Layout for Chemical Potential Control
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Solution Overview
Problem
Current quantum computing devices face challenges in achieving homogeneous electrostatic control and local control of chemical potential within quantum dots while ensuring the absence of charged particles outside the quantum dot matrix, with complex manufacturing processes and strict alignment constraints.
Innovation Solution
A semiconductor device with a matrix of quantum dots is designed, featuring self-aligned grids on a single lithography level, allowing for independent control of potential barriers and chemical potential through first, second, third, and fourth grids, ensuring no conductive layer screening, and a simplified manufacturing method that eliminates the need for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If three levels of grids are used to control quantum dot matrix, then control of chemical potential and potential barriers is improved, but device complexity increases and manufacturing becomes more difficult due to strict alignment constraints
Solution Approach 1:
The patent combines multiple grid functions into a single grid structure. The first grid performs both the function of controlling potential barriers between quantum dots and defining the quantum dot positions, eliminating the need for separate second and third grids. This merging reduces device complexity while maintaining full control capability over chemical potential and potential barriers.
Solution Approach 2:
The first grid is designed to perform multiple functions simultaneously: it controls potential barriers between adjacent quantum dots, defines quantum dot positions through its pattern, and enables independent adjustment of chemical potential in each quantum dot. This multi-functionality eliminates the need for multiple specialized grid levels, reducing manufacturing complexity.
2Manufacturing precision
If vias are used to control grids, then homogeneity between grids is improved, but alignment constraints become very strict and manufacturing process becomes complex
Solution Approach 1:
The patent extracts and eliminates the via structure from the device architecture. By removing the need for vias to connect grid levels, the invention eliminates the associated strict alignment constraints and complex manufacturing steps, while still achieving homogeneous electrostatic control through the simplified single-grid approach.
Solution Approach 2:
The invention segments the grid control function into a single planar layer rather than requiring multiple stacked levels connected by vias. This segmentation into a single manufacturable layer eliminates the alignment constraints between multiple levels while maintaining the ability to independently control each quantum dot's chemical potential and potential barriers.
3Ease of operation
If multiple grid levels are used, then control capability is improved, but screening of higher grid levels by lower grid levels results in strong disparity between grid levels
Solution Approach 1:
The patent merges the functions of multiple grid levels into a single first grid that is not screened by other structures. This eliminates the disparity problem where lower grid levels screen higher ones, as there is only one grid level performing all control functions. The single grid maintains uniform electrostatic influence across all quantum dots without hierarchical screening effects.
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 solution provides homogeneous electrostatic control and local control of chemical potential within each quantum dot, ensuring the absence of charged particles between rows and columns, while simplifying the manufacturing process by reducing alignment constraints and eliminating conductive layer screening.
Implementation Method 1
the confinement of the charged particles must be achieved in all three spatial dimensions. In the state of the art, such confinement can be achieved in two ways (which can be used in combination): structurally (by alternating materials along at least one spatial dimension) and/or electrostatically by applying a potential to a portion of conductive material (e.g. using a gate electrode)
Implementation Method 2
In the field of quantum computing, it is known to use quantum dots in which one or more charged particles can be trapped for manipulation. For this, the confinement of the charged particles must be achieved in all three spatial dimensions.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3~4B
AI summary
One aspect of the invention relates to a quantum device (QD) configured to be able to form a matrix of quantum dots (QD), the device (QD) comprising for this purpose: an active layer (AL) made of a semiconductor material; a plurality of first grids (G1) arranged in a plurality of rows (L1); a plurality of second grids (G2) arranged in a plurality of columns (CO) perpendicular to the rows (L1) of the plurality of rows (L1); a plurality of third grids (G3), each third grid (G3) of the plurality of third grids (G3) being arranged at the intersection of a row of the plurality of rows (L1) and a column of the plurality of columns (CO), each third grid (G3) being separated from the nearest third grids (G3), on a row (L1) by a first grid (G1) and on a column (CO) by a second grid (G2);a plurality of fourth grids (G4), each fourth grid (G4) being arranged between two second grids (G2) along the rows (LI) and between two first grids (G1) along the columns (CO). The third grids (G3) are configured to control the chemical potential of a portion of the active layer (CA) located directly above said third grid.