Nanowire Spin Qubit Gates on Opposite Lateral Faces

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Solution Overview

Problem

Existing quantum devices with qubits based on quantum boxes face challenges in electrostatic control due to the need for control grids at different levels, leading to either large pitch requirements or reduced electrostatic control.

Innovation Solution

An electronic device with semiconductor nanofilms featuring disjoint control grids arranged on opposite sides, where the first grids control the electrostatic potential of quantum boxes and the second grids control the tunnel coupling between them, with all first grids on one side and all second grids on the opposing side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If all control gates are arranged in the same gate level, then the device structure is simplified, but the pitch between gates becomes relatively large requiring more space

Engineering Contradiction:
Improvegate structure complexityVSAvoidgate pitch area
Core Design Contradiction:
Device complexityVSArea of stationary object

Solution Approach 1:

The patent transitions from a two-dimensional planar gate arrangement to a three-dimensional configuration by placing control gates on opposite lateral faces of the nanowire. This spatial dimensionality change allows gates to be positioned closer together in effective pitch while maintaining electrical isolation, resolving the contradiction between structural simplicity and area efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If control gates are placed in different gate levels, then the gate pitch area is reduced, but the electrostatic control of the gates deteriorates

Engineering Contradiction:
Improvegate pitch areaVSAvoidelectrostatic control
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

Instead of stacking gates vertically in different levels, the patent positions control gates on opposite lateral faces of the nanowire. This lateral separation in three-dimensional space achieves compact pitch while maintaining strong electrostatic control, as each gate remains close to the nanowire surface without vertical stacking complications.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies different gate configurations to different spatial locations: potential control gates are placed on one lateral face while coupling control gates are placed on the opposite lateral face. This localized positioning optimizes electrostatic control for each specific function while achieving compact overall device dimensions.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If gates controlling coupling are placed farther from the semiconductor, then manufacturing becomes easier, but electrostatic control of these gates becomes less effective

Engineering Contradiction:
Improvegate fabricationVSAvoidelectrostatic control
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent positions coupling control gates on the opposite lateral face of the nanowire rather than placing them far away in the same plane. This three-dimensional positioning maintains effective electrostatic control by keeping gates close to the active region while providing sufficient manufacturing access and isolation from other device components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enables strong electrostatic control of quantum boxes and tunnel coupling between them, improving the overall performance of quantum devices by reducing unwanted electrical contacts and enhancing control precision.

Implementation Method 1

gates controlling the coupling between neighboring quantum dots and gates controlling the potentials of the quantum dots

Methodology Applied
Scientific EffectElectrostatic potential control: Electrostatics

Implementation Method 2

quantum dots are formed by grids through which electrical confinement potentials are created

Methodology Applied
Scientific EffectElectrical confinement: Electric Field

Implementation Method 3

quantum dots that ensure the confinement of elementary charges (electrons or holes)

Methodology Applied
Scientific EffectQuantum confinement: Potential Well

Implementation Method 4

It is also necessary to be able to electrically control the tunnel coupling, i.e., the height of the tunnel barriers, between neighboring quantum dots

Methodology Applied
Scientific EffectQuantum tunneling:

Data Source

PatentEP4554353A1Spin qubit device comprising quantum dots formed in a nanowire by gates
Publication Date: 2025.05.14 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4554353A1 patent drawingFigure 1~3
  • EP4554353A1 patent drawingFigure 4~6
  • EP4554353A1 patent drawingFigure 7~9

AI summary

The present description relates to an electronic device (100) comprising: - a semiconductor nanowire (104); - at least two disjoint first control gates (106), arranged side by side on the side on a first lateral face (108) of the nanowire, and configured to each control the electrostatic potential of a quantum dot (114) intended to be formed in the nanowire; - at least one second control gate (116) arranged on the side of a second lateral face (118), opposite to the first lateral face, of the nanowire, and configured to control the electrostatic potential of a coupling region intended to be formed between two quantum dots; wherein all the first control gates are arranged only on the side of the first lateral face, and the second control gate(s) are arranged only on the side of the second lateral face;and in which no part of the second grid (116) is arranged between the first grids (106).;