Carbon Membrane Particle Filter for Charged Detector Protection
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Solution Overview
Problem
Conventional charged particle detectors are sensitive to diverse types of particles, leading to significant noise content and degradation due to sputtered material deposition and ion implantation, making them incompatible with operating conditions that result in sputtered material deposition on detector surfaces.
Innovation Solution
A filter comprising a frame and a carbon material membrane is coupled with the detector, configured to shield the absorption surface from particles, and can apply a bias voltage to selectively repel or transmit electrons based on energy, thereby protecting the detector from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter material is selected to be robust under operating conditions, then the detector reliability is improved, but the filter may introduce artefacts in detector data
Solution Approach 1:
The patent employs a porous carbon filter material with controlled pore size and structure. The porous nature allows the filter to be sufficiently thin to minimize artefact introduction while maintaining robustness against particle damage. The pore structure enables selective particle interaction, allowing the filter to protect the detector without significantly degrading the detection signal.
Solution Approach 2:
The patent uses carbon-based composite materials with specific structural properties. The carbon material provides both mechanical robustness under ion bombardment and appropriate interaction characteristics for particle filtration. The composite structure balances durability with transparency to detection signals, resolving the contradiction between reliability and data quality.
2Adaptability or versatility
If the detector is exposed to sputtered material, then the detector can detect particles in FIB processing environments, but the dark current increases due to conductive layer formation
Solution Approach 1:
The patent introduces a carbon filter as an intermediary layer between the sputtered material environment and the detector. This intermediary allows the detector to operate in FIB processing environments by filtering out harmful sputtered particles and ions while permitting detection signals to pass through. The filter prevents conductive layer formation on the detector surface, thereby maintaining low dark current levels.
3Adaptability or versatility
If the detector is exposed to FIB ions and sputtered material, then the detector can operate in ion beam systems, but the charge collection efficiency is impaired
Solution Approach 1:
The patent converts the harmful effect of ion bombardment into a beneficial protective mechanism. The carbon filter material is specifically chosen to be resistant to ion damage while effectively blocking ions and sputtered material from reaching the detector. This allows the detector to operate in ion beam systems without efficiency degradation, as the filter absorbs the ion damage that would otherwise impair charge collection.
4Productivity
If a thin layer of sputtered material is deposited on the detector, then the detector can detect particles, but the quantum detection efficiency is impaired
Solution Approach 1:
The patent applies preliminary protective action by placing the carbon filter before the detector to prevent sputtered material deposition. The filter acts as a sacrificial barrier that accumulates sputtered material before it can reach the detector surface. This preliminary protection maintains quantum detection efficiency by preventing the formation of efficiency-degrading material layers on the detector.
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 filter improves detector performance by reducing noise and degradation, serving as a variable energy filter and collector for charged particles, enhancing the robustness and longevity of the detector.
Implementation Method 1
the filter can apply a bias voltage to selectively repel or transmit electrons based on energy
Implementation Method 2
The filter can be configured to shield the absorption surface from particles incident on the second surface
Data Source
AI summary
Systems, components, and methods are described for protecting a charged particle detector against damage. A filter can include a frame and a membrane of carbon material. The membrane can define a first surface, a second surface opposing the first surface, and an aperture extending through the membrane from the first surface to the second surface. The frame can be configured to couple with a charged particle detector disposed in a charged particle beam column, the charged particle detector defining an absorption surface oriented toward the first surface. The filter can be configured to shield the absorption surface from particles incident on the second surface. The particles can include electrons, ions, or photons.