Quantum Dot Devices With Vertical Fins For Spatial Localization
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Solution Overview
Problem
Existing quantum computing technologies face challenges in achieving strong spatial localization of quantum dots, good scalability, and effective control over quantum dot interactions and manipulation.
Innovation Solution
The development of quantum dot devices with a substrate and a quantum well stack, including a back gate disposed between the quantum well layer and the substrate, enables the formation of quantum dots as quantum bits (qubits) and provides control over these quantum dots for quantum logic operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If quantum dots are formed without fins, then device structure is simpler, but spatial localization of quantum dots is weaker
Solution Approach 1:
The patent introduces vertical fins that extend upward from the substrate, adding a vertical dimension to the quantum dot confinement structure. This vertical dimensionality enhancement provides stronger spatial localization of quantum dots by creating three-dimensional potential wells, while the fins can be periodically arranged to maintain fabrication compatibility with standard semiconductor processes.
Solution Approach 2:
The quantum well layer is segmented into multiple discrete quantum dots by the vertical fins, which act as separating structures. This segmentation creates isolated potential wells that strongly localize quantum dots in space, while the periodic arrangement of fins allows scalable fabrication using standard lithography and etching techniques.
2Reliability
If quantum dots are strongly localized, then control over quantum dot interactions is improved, but scalability is reduced
Solution Approach 1:
The patent enables independent control of quantum dot properties by applying voltages to gates positioned above each fin. This allows tuning of quantum dot energy levels, sizes, and interaction strengths through electrical parameter changes, providing reliable control over quantum dot interactions while maintaining scalability through electrical programming rather than physical restructuring.
Solution Approach 2:
The periodic fin structure serves multiple functions: it provides strong spatial localization through vertical confinement, enables scalable fabrication through periodic repetition, and allows individual addressability through associated gates. This multi-functionality resolves the contradiction between strong localization and scalability.
3Ease of operation
If back gate is positioned closer to quantum well layer, then control over quantum dots is enhanced, but electrical connection design becomes more complex
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the back gate and the quantum well layer. This intermediary allows the back gate to be positioned close to the quantum well for enhanced control while maintaining proper electrical isolation and enabling standard fabrication processes, thus resolving the contradiction between control enhancement and design complexity.
Data Source
AI summary
Disclosed herein are quantum dot devices, as well as related computing devices and methods. For example, in some embodiments, a quantum dot device may include: a substrate and a quantum well stack disposed on the substrate. The quantum well stack may include a quantum well layer and a back gate, and the back gate may be disposed between the quantum well layer and the substrate.