Ion Gun Vacuum Cluster Ion Source Low-Damage Sputtering
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Solution Overview
Problem
Current surface analysis methods, such as secondary ion mass spectroscopy (SIMS), face challenges with sample damage and low secondary ion yield, particularly when analyzing organic and inorganic materials, and existing ion sources fail to provide effective low-damage sputtering and high sensitivity across various sample types.
Innovation Solution
An analysis instrument with a vacuum-based ion gun that generates super large droplet cluster ions using a capillary with a conductive surface, where the ionization liquid is supplied and electrospray is stabilized by a laser, allowing for low-damage sputtering and enhanced secondary ion yield through the formation of a focused cluster ion beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional ion sources (noble gas ions, metal ions, or atmospheric cluster ions) are used for sputtering, then secondary ion yield is improved, but sample damage increases significantly
Solution Approach 1:
The invention changes the fundamental parameters of the ion beam by using super large droplet cluster ions (containing thousands to millions of atoms) instead of conventional small cluster ions or monatomic ions. This parameter change enables simultaneous achievement of high secondary ion yield and minimal sample damage, resolving the technical contradiction between quantity of secondary ions and sample damage.
Solution Approach 2:
The invention uses composite ion structures (super large droplet clusters containing multiple atoms of different elements) as primary ions for sputtering. These composite cluster ions interact with the sample surface in a unique manner that generates abundant secondary ions while causing minimal damage to the sample, thereby resolving the contradiction between secondary ion yield and sample damage.
2Object-affected harmful factors
If argon gas cluster ion beam (GCIB) is used for low-damage sputtering of organic materials, then sample damage is reduced, but sputtering speed becomes extremely slow for inorganic materials
Solution Approach 1:
The invention changes the size parameter of cluster ions from conventional small clusters to super large droplet clusters containing thousands to millions of atoms. This parameter change enables the ion beam to effectively sputter both soft organic materials and hard inorganic materials at practical speeds while maintaining low damage characteristics, thereby resolving the contradiction between sample damage and sputtering speed.
3Ease of manufacture
If atmospheric charged droplet method is used to generate cluster ions, then ion generation is simplified, but ion scattering increases due to collisions with gas molecules
Solution Approach 1:
The invention applies preliminary action by generating the ionization liquid electrospray inside the vacuum chamber before the ions can collide with gas molecules. This preliminary generation in vacuum prevents ion scattering and maintains beam quality, while still using the relatively simple electrospray generation method.
Solution Approach 2:
The invention uses vacuum as an inert environment to prevent collisions between generated cluster ions and gas molecules. By generating ions in this inert vacuum atmosphere rather than in atmospheric conditions, the ion beam maintains high quality with minimal scattering, resolving the contradiction between ease of ion generation and ion beam quality.
4Power
If high voltage is applied to capillary and extraction electrodes in atmospheric conditions, then ion extraction is achieved, but discharge phenomenon occurs and beam stability decreases
Solution Approach 1:
The invention relocates the ion generation and extraction process from atmospheric conditions to vacuum conditions. In this inert vacuum environment, high voltage can be applied to the capillary and extraction electrodes for effective ion extraction without causing discharge phenomena, thereby achieving both power capability and beam stability.
5Productivity
If conventional ion sources are used for SIMS analysis, then analysis speed is maintained, but sensitivity is limited due to low secondary ion yield
Solution Approach 1:
The invention changes the key parameter of primary ion size from conventional small ions to super large droplet clusters containing thousands to millions of atoms. This parameter change dramatically increases secondary ion yield, thereby improving measurement sensitivity while maintaining analysis speed, resolving the contradiction between productivity and measurement precision in SIMS analysis.
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 depth profile analysis of various materials with minimal damage and improved sensitivity, expanding the range of analyzable samples beyond organic materials and enhancing the utility of SIMS by increasing secondary ion yield and stability of the cluster ion beam.
Implementation Method 1
a laser beam emitting device (106) configured to irradiate the emission opening with a laser beam
Implementation Method 2
an ion source for low damage sputtering... an extracting electrode configured to extract ions in the ionization liquid supplied from the ionization liquid supply device to the emission tube, as cluster ions
Implementation Method 3
low damage sputtering regardless of materials (such as, an inorganic or organic material)... depth profile analysis of various materials with minimal damage
Implementation Method 4
an analysis instrument comprising an ion source... a vacuum-based ion gun... a vacuum chamber
Data Source
Figure 1-1~1-2
Figure 2-1
Figure 2-2
AI summary
Provided are an ion source, an ion gun, and an analysis instrument, which are capable of performing sputtering without damage to a surface of a sample and improving detection sensitivity in mass spectroscopy. In the ion source (102), an emission opening (135) to which ionization liquid is supplied is disposed in an electric field formed in vacuum environment by an extracting electrode (122) so that super large droplet cluster ions (145) are generated from the emission opening (135). When the sample is irradiated with a super large droplet cluster ion beam, the sample surface is subjected to sputtering without damage, so as to remove contamination substances or to expose a new surface of the sample. In mass spectroscopy, detection sensitivity is improved.