Multilayer Ion Trap Electrodes With Ra ≤ 5 Nm Surface Roughness

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Solution Overview

Problem

Current ion traps face challenges in controlling and scaling the number of qubits for quantum computing due to increased requirements for device control and interference suppression as the number of ions increases, with surface electrodes contributing to issues like capacitive charging, light scattering, and unwanted heating.

Innovation Solution

A micro-fabricated device with a structured electrode layer formed from a multilayer stack, including an electrically conductive smoothing layer and a top layer with a mean surface roughness of Ra ≤ 5 nm, which reduces surface roughness and minimizes adverse effects such as heating and light scattering, allowing for improved control and scalability of trapped ions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If surface electrodes are used in ion traps, then electrical conductivity for handling capacitive charging currents is improved, but surface roughness causes unwanted heating and light scattering of ions

Engineering Contradiction:
Improveelectrical conductivityVSAvoidheating and light scattering
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The electrode is constructed as a composite structure with a rough underlying layer providing high electrical conductivity for capacitive charging currents, and an overlying smoothing layer with low surface roughness (Ra ≤ 5 nm) that reduces heating and light scattering of ions. This composite approach allows both high conductivity and low surface roughness to coexist.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The electrode surface is segmented into functional layers: a bottom layer that handles electrical conductivity requirements and a top smoothing layer that handles optical and thermal requirements. This segmentation allows each layer to optimize for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If the number of ions is increased for quantum computing, then computational power is improved, but device control complexity and interference suppression requirements increase

Engineering Contradiction:
Improvenumber of ionsVSAvoidcontrol and interference suppression
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The smoothing layer is applied specifically to the electrode surfaces that directly interact with ions, providing localized quality improvement where it is most needed for reducing heating and light scattering, while the overall device structure can continue to scale with increased ion numbers.

Inventive Principle:
Principle #3Local quality

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

The solution enables efficient control and scalability of ion traps by reducing surface roughness, minimizing heating and light scattering, and enhancing the trapping capability, thus supporting the development of more advanced quantum computing systems.

Implementation Method 1

surface impurities and light scattering from the electrode surfaces can be kept low

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

surface electrodes can cause unwanted heating of the ions, which should be minimized

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4404215A1Device for controlling trapped ions with an electrode layer of low surface roughness
Publication Date: 2024.07.24 INFINEON TECH AUSTRIA AG
  • EP4404215A1 patent drawingFigure 1~3
  • EP4404215A1 patent drawingFigure 4~6
  • EP4404215A1 patent drawingFigure 7~9C

AI summary

A micro-fabricated device (100, 200, 400) for controlling trapped ions (180) includes a substrate (120, 150). A structured electrode layer (155) is disposed over the substrate. The structured electrode layer forms a plurality of electrodes of an ion trap configured to trap ions in a space above the structured electrode layer. The structured electrode layer is formed of a multilayer stack. The multilayer stack includes an electrically conductive smoothing layer (520) having a planarized surface (520A) and an electrically conductive top layer (540) disposed over the planarized surface of the smoothing layer. The top layer provides an exposed surface (540A) of the structured electrode layer, the exposed surface having a mean surface roughness equal to or less than Ra = 5 nm.