Bumped Resonator Structure for Superconducting Qubit Coherence

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Solution Overview

Problem

Current superconducting quantum computing technologies face challenges in scaling up due to introduction of lossy materials and connections, which limit qubit coherence times and degrade performance, particularly in transition and connection regions of superconducting qubit circuits.

Innovation Solution

A compact lumped element resonator structure spanning two superconducting circuit planes, where capacitive energy is maintained on one plane and inductive energy on the other, keeping electrical currents off the qubit plane and on the readout path, with well-controlled electromagnetic fields to avoid coupling with lossy parts of the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If superconducting qubit circuits use traditional planar structures with all components on the same plane, then fabrication is simpler, but lossy materials and connections are introduced that limit qubit coherence times

Engineering Contradiction:
Improvequbit coherence timeVSAvoidcircuit structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from a traditional planar two-dimensional layout to a three-dimensional stacked architecture where capacitive elements are positioned on a first plane and inductive elements on a second plane separated by a dielectric layer. This vertical stacking eliminates the need for lossy interconnect materials between qubits while maintaining electrical connectivity through controlled electromagnetic coupling between the stacked layers, thereby improving qubit coherence time without excessive fabrication complexity.

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

2Reliability

If all circuit components are placed on the same plane, then device layout is simpler, but electrical currents pass through lossy interconnect regions degrading performance

Engineering Contradiction:
ImproveperformanceVSAvoiddevice layout
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention separates capacitive and inductive components onto different vertical planes with a dielectric layer in between, allowing electrical currents to flow on the first plane while magnetic fields are confined to the dielectric region. This spatial separation eliminates current passage through lossy interconnect regions, improving performance while maintaining manufacturability through standard layered fabrication techniques.

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

3Reliability

If compact lumped element resonator structure is used with separated planes, then lossy components are isolated from qubits, but fabrication process becomes more complex

Engineering Contradiction:
Improvequbit coherenceVSAvoidfabrication process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements a vertically stacked configuration where the capacitive element resides on a first substrate plane, the inductive element on a second substrate plane, separated by a dielectric layer. This three-dimensional arrangement isolates lossy interconnect components from the qubit region while utilizing standard semiconductor fabrication processes for depositing and patterning multiple layers, making the enhanced coherence compatible with existing manufacturing capabilities.

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

4Reliability

If traditional planar resonator structure is used, then footprint is larger, but electromagnetic field control is less precise

Engineering Contradiction:
Improveelectromagnetic field controlVSAvoiddevice footprint
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

By stacking capacitive and inductive elements vertically with precise spacing through a dielectric layer, the patent achieves compact lumped element resonator structures that confine electromagnetic fields to specific three-dimensional regions. This vertical integration dramatically reduces the horizontal footprint while providing superior control over electromagnetic field distributions through precise geometric configuration of the stacked 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 approach enhances qubit coherence by isolating lossy components from qubits and interconnects, maintaining a small footprint and reducing decoherence effects, thus facilitating the scaling of superconducting quantum computing hardware.

Implementation Method 1

a capacitive element having a first portion on a first surface and a second portion on a second surface, the first and second portions having an equipotential

Methodology Applied
Scientific EffectSuperconductivity: Superconductivity

Implementation Method 2

A non-limiting example of the structure includes an inductive element on a first surface, a capacitive element on the first surface and a second surface

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3718166B1Bumped resonator structure
Publication Date: 2022.07.20 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP3718166B1 patent drawingFigure 1
  • EP3718166B1 patent drawingFigure 2
  • EP3718166B1 patent drawingFigure 3

AI summary

A resonator structure that can be utilized with superconducting qubit circuits. An inductive element is on a first surface. A capacitive element is on the first surface and a second surface. An interconnect structure is between the first surface and the second surface.