Deflector Unit in Gun Lens for Emission Peak Selection
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Solution Overview
Problem
Existing charged particle beam devices face challenges in achieving high throughput due to limited beam current, which is influenced by the emission area and crystal orientation of field emitters, leading to variations in brightness and stability.
Innovation Solution
A charged particle beam apparatus with a deflector unit integrated into the gun lens, positioned close to the emitter, allows for the selection of specific emission peaks from the emission pattern by directing them through a diaphragm, enhancing brightness and stability by reducing electron-electron interactions and aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a field emitter with multiple emission areas is used to increase beam current, then the charged particle beam current increases, but the brightness and stability vary significantly due to different crystal surfaces
Solution Approach 1:
The emission pattern of the field emitter is segmented into multiple discrete emission peaks corresponding to different crystal surfaces. The deflector unit enables selective extraction of individual emission peaks, allowing the system to use multiple emission areas while maintaining stability by choosing only the most stable peaks for operation.
Solution Approach 2:
The system measures the emission pattern to identify peaks with high brightness and stability characteristics. This measurement feedback is used to control the deflector unit, which then directs the selected stable emission peak through the diaphragm, ensuring consistent and reliable beam current.
2Ease of operation
If mechanical alignment methods are used to determine emission area, then the emission area can be selected, but the alignment process is rough and imprecise
Solution Approach 1:
The mechanical alignment method is replaced with an electromagnetic deflection system. The deflector unit uses electric or magnetic fields to precisely steer the electron beam, allowing for accurate selection of emission peaks without the imprecision of mechanical alignment procedures.
Solution Approach 2:
Instead of mechanically adjusting the emitter position and orientation, the system changes the deflection parameters (electric or magnetic field strength and direction) to steer different emission peaks through the diaphragm. This provides continuous and precise control over emission area selection.
3Reliability
If the gun lens and deflector unit are positioned close to the emitter, then electron-electron interactions and aberrations are reduced, but the device complexity increases
Solution Approach 1:
The deflector unit is integrated into the gun lens assembly, merging two functional components into a single compact structure. This integration reduces the overall distance from the emitter while maintaining both the focusing and deflection functions, thereby reducing aberrations without proportionally increasing complexity.
Solution Approach 2:
The gun lens structure is designed to serve multiple functions: it provides both the focusing action of the lens and houses the deflector unit for beam steering. This multi-functionality allows close positioning to the emitter for improved beam quality while minimizing the increase in device complexity through shared structural elements.
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 enables precise localization of high-brightness and stable emission areas, simplifies beam alignment, and allows for varying beam current for different applications, improving overall throughput and reducing the need for complex alignment methods.
Implementation Method 1
a deflector unit, and a diaphragm wherein the gun lens comprises the deflector unit and the deflector unit is adapted to direct an emission peak
Implementation Method 2
a gun lens, and a diaphragm wherein the gun lens comprises the deflector unit
Implementation Method 3
When applying a voltage to the cold field emitter, a very strong electric field is formed at the emitter tip due to its small radius of curvature. The strong electric field enables the electrons to pass the potential barrier between the metal and the vacuum
Data Source
AI summary
A charged particle beam apparatus and a method for measuring an emission pattern of such an apparatus are provided. The apparatus comprises an emitter with an emission pattern including at least two emission peaks, a gun lens, and a diaphragm, wherein the gun lens comprises a deflector unit and the deflector unit is adapted to direct an emission peak of the at least two emission peaks to an opening of the diaphragm to thereby select the emission peak of the at least two emission peaks from the emission pattern.