Back-to-Back Silicon Qubit Structure for Electrostatic Confinement
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Solution Overview
Problem
Existing silicon-based quantum computing devices lack satisfactory electrostatic control and confinement of carriers in qubits, limiting the entanglement and stability of quantum states.
Innovation Solution
A semiconductor qubit device with a back-to-back configuration of two semiconductor substrates, featuring a doped well that enhances electrostatic control and confinement along both lateral and vertical directions, utilizing a plunger and barrier gate structure to manage carriers in quantum dot qubit regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silicon-based quantum devices are used, then device fabrication is relatively simple, but electrostatic control and confinement of carriers in qubits is insufficient
Solution Approach 1:
The device is segmented into two separate substrates (first substrate and second substrate) with qubit regions formed on opposite sides. This segmentation allows independent optimization of electrostatic control on each substrate while maintaining overall device functionality, resolving the contradiction between improved electrostatic control and device complexity.
Solution Approach 2:
A doped well structure is formed within each substrate, nesting the quantum dot qubit regions within the electrostatic potential wells created by the doped regions. This nested structure provides enhanced carrier confinement while maintaining a relatively simple fabrication process, addressing the technical contradiction.
2Reliability
If electrostatic control is enhanced through additional structures, then carrier confinement improves, but device complexity increases
Solution Approach 1:
The doped well structures serve multiple functions simultaneously: they provide carrier confinement, define quantum dot regions, and act as electrostatic gates. This multi-functionality improves carrier confinement without proportionally increasing device complexity, as the same structures perform multiple critical roles.
Solution Approach 2:
The invention transitions from planar electrostatic control to three-dimensional control by forming doped wells that extend vertically through the substrate thickness. This dimensional change provides enhanced carrier confinement in the vertical direction without requiring additional lateral structures, effectively resolving the contradiction.
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
Improves entanglement between quantum dots by providing enhanced electrostatic control and confinement, leading to more stable eigenstates and improved quantum computing performance.
Implementation Method 1
a doped well that enhances electrostatic control and confinement along both lateral and vertical directions
Data Source
AI summary
A semiconductor device includes a first substrate having a first frontside and a first backside opposite the first frontside. The semiconductor device includes first source/drain (S/D) features over the first frontside. The semiconductor device includes a first barrier gate and a first plunger gate between the first S/D features, where the first plunger gate defines a first quantum bit region. The semiconductor device includes a second substrate having a second frontside and a second backside opposite the second frontside. The semiconductor device includes second S/D features over the second frontside. The semiconductor device includes a second barrier gate and a second plunger gate between the second S/D features, where the second plunger gate defines a second quantum bit region aligned with the first quantum bit region along the first direction. The semiconductor device includes a doped well extending between the first backside and the second backside along the first direction.