Ultra Sharp Tip Preparation via Field Evaporation and Coating Restoration

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Solution Overview

Problem

Existing methods for preparing ultra sharp tips, such as single atom tips, require complex cleaning procedures and highly controlled environments due to contamination issues and surface roughness, which complicates the formation of ultra sharp tips for applications like electron or ion sources.

Innovation Solution

A method involving a vacuum chamber with a field evaporation device and a coating restoring device is used to locally remove and then partially or fully restore the coating on the tip apex, allowing for the formation of ultra sharp tips using standard equipment and in situ processing, thereby minimizing surface roughness and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If complex cleaning procedures and highly controlled environments are used to prepare ultra sharp tips, then the tip surface purity and smoothness are improved, but the device complexity and process complexity increase

Engineering Contradiction:

Improvetip surface smoothnessVSAvoidcleaning procedure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The tip performs self-cleaning through field evaporation of contaminants at the apex during normal operation, eliminating the need for complex external cleaning procedures. The high electric field at the tip apex automatically removes contaminants through field evaporation, making the system self-maintaining.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Mechanical or chemical cleaning methods are replaced by field evaporation using high electric fields. Instead of using complex cleaning equipment or chemical etchants, the patent uses electrical field action to remove contaminants and shape the tip apex atom by atom.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If field evaporation is used to locally remove coating from the apex, then the tip surface purity is improved, but the loss of coating material occurs

Engineering Contradiction:

Improvetip surface purityVSAvoidcoating material loss

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

Field evaporation is applied locally only at the tip apex where the electric field is strongest, rather than uniformly across the entire tip. This localized action removes contaminants and shapes the apex while minimizing material loss from the bulk of the tip structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Only the necessary amount of coating material is removed from the apex through field evaporation, extracting just enough material to achieve the desired sharpness and purity without excessive loss. The process selectively removes material only where needed at the apex region.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method simplifies the preparation of ultra sharp tips by using field evaporation to clean and reshape the tip surface, resulting in atomic smoothness and improved performance for applications like electron or ion sources, while reducing the need for complex cleaning and controlled environments.

Implementation Method 1

locally removing the coating from the apex by field evaporation

Methodology Applied

Scientific EffectField evaporation:

Implementation Method 2

Different processes to deposit the coating on the base tips are known, e.g. electroplating or vapor deposition

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentEP2144274B1Method of preparing an ultra sharp tip and use of an apparatus therefor

Publication Date: 2012.09.12 ICT INTEGRATED CIRCUIT TESTING GESELLSCHAFT FUER HALBLEITERPRUEFTECHNIK GMBH

Figure 1A~1B
Figure 2A~2C
Figure 3A~3C

AI summary

A method of preparing an ultra sharp tip, in particular a single atom tip, is provided, comprising providing a tip (11) having a shank (15), an apex (16), and a coating (14,17,18) covering the shank and the apex; locally removing the coating (14) from the apex (16) by field evaporation; and partially or fully restoring the coating at the apex (16).