Gas Field Ion Source Emitter Tip Crystal Structure Restoration
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Solution Overview
Problem
Existing methods fail to reproducibly narrow the radiation angle of a focused ion beam while maintaining the crystal structure of a gas field ion source emitter at its original state, which is crucial for achieving high resolution and long emitter lifespan.
Innovation Solution
A manufacturing method involving electropolishing and electric field-induced gas etching processes to sharpen the emitter tip, followed by heating to rearrange atoms, creating a nanopyramid structure with a vertex angle of 90 degrees or more, which reduces the number of atoms at the tip and maintains the crystal structure's original state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the emitter tip is sharpened to reduce the number of atoms at the tip to generate a focused ion beam with small beam diameter, then the beam diameter is reduced and resolution is improved, but the crystal structure becomes fragile and changes from its original state
Solution Approach 1:
The patent applies preliminary heating treatment to the emitter tip before use to rearrange atoms and restore the crystal structure to its original state. This preliminary action prevents crystal structure degradation that would otherwise occur during FIB operation, ensuring stable performance throughout the emitter's lifespan.
Solution Approach 2:
The patent changes the temperature parameter by heating the emitter tip to a specific temperature range (700-900°C) during the treatment process. This parameter change enables atom rearrangement and crystal structure restoration without altering the emitter's physical shape or composition.
2Stability of the object's composition
If heating treatment is applied to restore the crystal structure, then the crystal structure returns to its original state, but the radiation angle of the ion beam may increase
Solution Approach 1:
The patent applies heating treatment locally to the emitter tip region rather than the entire emitter. This localized treatment restores the crystal structure at the critical tip area where atom rearrangement affects beam properties, while maintaining the overall emitter geometry and controlling the radiation angle.
3Productivity
If the emitter is used for an extended period to increase productivity, then more samples can be processed, but the crystal structure degrades and extraction voltage increases
Solution Approach 1:
The patent implements periodic heating treatment during FIB operation to periodically restore the crystal structure. This periodic maintenance action prevents cumulative crystal structure degradation that would otherwise occur with continuous use, extending the emitter's productive lifespan while maintaining performance.
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 allows for a high-reproducibility return of the emitter's crystal structure to its original state, narrowing the ion beam's radiation angle, increasing the emission current, and extending the emitter's lifespan by maintaining optimal extraction voltage values.
Implementation Method 1
an electropolishing process electrolytically polishing a front end portion of a conductive emitter material
Implementation Method 2
an etching process further sharpening the front end by an electric field-induced gas etching processing
Implementation Method 3
by heating the front end of the emitter to, for example, about 700° C. to 900° C., the treatment rearranges the atoms so the crystal structure is returned to its original state
Implementation Method 4
the gas is ionized by field ionization in a high electric field at a front end portion of the emitter
Data Source
AI summary
A method of manufacturing an emitter is disclosed. The method enables a crystal structure of the tip of the front end of the emitter to return to its original state with high reproducibility by rearranging atoms in a treatment, and enables a long lasting emitter to be attained by suppressing extraction voltage rise after the treatment. As a method of manufacturing an emitter having a sharpened needle-shape, the method includes: performing an electropolishing process for the front end of an emitter material having conductivity to taper toward the front end; and performing an etching to make the number of atoms constituting the tip of the front end be a predetermined number or less by further sharpening the front end through an electric field-induced gas etching having constantly applied voltage, while observing the crystal structure of the front end, by a field ion microscope, in a sharp portion having the front end at its apex.