Quantum Circuit Gate Layout Using Spacers for R/4 Pitch

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Solution Overview

Problem

Existing quantum electronic circuits face challenges in achieving high integration density and low circuit variability while forming quantum dots with reduced widths, typically less than 80 nm, without requiring expensive EUV lithography steps, and face issues with misalignment and short-circuiting due to small grid pitches.

Innovation Solution

A method involving the formation of first, second, and third grid electrodes on a substrate, where the second and third electrodes are inserted between pairs of first electrodes, reducing the final grid pitch to R/4, allowing for quantum dot formation with minimal influence from electrostatic charges, and ensuring easy re-establishment of electrical contacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional manufacturing methods are used, then the fabrication process is simpler, but the gate pitch cannot be reduced below a certain limit

Engineering Contradiction:
Improvegate pitchVSAvoidfabrication process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fabrication process is divided into multiple sequential steps: forming first electrodes at pitch R, forming spacers against these electrodes, forming second electrodes between spacers, and finally replacing spacers with third electrodes. This segmentation allows achieving R/4 pitch through systematic breakdown of the manufacturing process into manageable stages, each contributing to the final reduced pitch.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from direct planar patterning to a multi-dimensional approach using vertical spacers and sequential electrode formation. By utilizing the vertical dimension for spacer formation and then translating this into horizontal pitch reduction, the process achieves R/4 pitch that would be impossible with conventional single-plane manufacturing methods.

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

2Productivity

If the gate pitch is reduced to increase transistor density, then the computational power increases, but the fabrication precision requirements become more stringent

Engineering Contradiction:
Improvetransistor densityVSAvoidelectrode positioning precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The spacer formation step serves a dual purpose: it defines the position for subsequent second electrodes while simultaneously establishing the R/4 pitch pattern. The spacers self-align to the first electrodes, and their width directly determines the final pitch, eliminating the need for separate high-precision alignment steps and reducing overall manufacturing precision requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The method performs preliminary actions by first forming electrodes at the relaxed pitch R, then using spacers to pre-establish the R/4 pitch pattern before final electrode formation. This preliminary structuring allows subsequent steps to proceed at lower precision requirements, as the critical pitch definition is already established by the spacer geometry rather than requiring high-precision direct patterning.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4554356B1Method for manufacturing a quantum electronic circuit with reduced gate pitch
Publication Date: 2026.05.13 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4554356B1 patent drawingFigure 1~3
  • EP4554356B1 patent drawingFigure 4~5
  • EP4554356B1 patent drawingFigure 6~7

AI summary

One aspect of the invention relates to a method for manufacturing an electronic circuit (1) comprising the steps of: - forming first electrodes (51) distributed according to a constant pitch R; - forming spacers against the first electrodes (51); - forming, between two adjacent spacers, a second electrode (52); and - replacing each spacer with a third electrode (53). The first, second, and third electrodes (51, 52, 53) are thus distributed according to an average pitch equal to R/4.