Metallic Ion Source Dual Chamber Segmentation
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Solution Overview
Problem
Existing ion sources face challenges in generating high-density ions efficiently due to difficulties in maintaining identical vacuum levels for electron evaporation and ionization, leading to electric discharge issues and restricted ion beam directionality, which hinders the development of compact and lightweight ion sources for applications like thin-film formation.
Innovation Solution
A metallic ion source with a dual evaporation-plasma chamber and differential exhaustion structure maintains high vacuum levels in the electron beam generation and ion extraction chambers, allowing high-speed electron beams to efficiently evaporate and ionize precursor gases independently, while enabling selection of discharge types and ion extraction direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gas pressure in the evaporation region is raised to increase electron collision cross-section, then ionization efficiency improves, but electron beam collision with precursor gas degrades evaporation efficiency
Solution Approach 1:
The invention divides the vacuum chamber into two separate regions: an electron beam generation region maintained at low pressure (10^-3 to 10^-6 Torr) to prevent discharge and ensure electron beam formation, and an evaporation/ionization region maintained at higher pressure (10^-1 to 10 Torr) to enable efficient ionization. A partition wall with a small aperture connects these regions, allowing precursor gas diffusion while maintaining pressure differential. This segmentation resolves the contradiction by allowing each region to operate at its optimal pressure independently.
2Quantity of substance
If the vacuum level is lowered to improve ionization, then ion density increases, but electric discharge occurs in the electron gun preventing beam formation
Solution Approach 1:
The invention separates the electron gun region from the evaporation region using a partition wall. The electron gun region maintains high vacuum (10^-3 to 10^-6 Torr) for reliable electron beam formation, while the evaporation region operates at higher pressure (10^-1 to 10 Torr) for high ion density. The partition wall with a small aperture allows controlled gas diffusion while maintaining pressure differential, resolving the contradiction between ion density and electron beam reliability.
3Productivity
If discharge electrodes are placed near the evaporation source to enhance ionization, then ion production improves, but the electric field deflects the electron beam spoiling its directivity
Solution Approach 1:
The invention places discharge electrodes in the evaporation region away from the electron beam path, utilizing the partition wall to spatially separate beam generation and ionization functions. The electron beam travels through a clear path in the high-vacuum region, while ionization occurs in the separate evaporation region, eliminating electric field interference with beam directivity while maintaining high ion production.
Solution Approach 2:
The partition wall with a small aperture acts as an intermediary structure that enables precursor gas to diffuse from the evaporation region to the electron beam region, where it can be ionized without interfering with the electron beam path. This intermediary arrangement allows ionization to occur near the evaporation source while protecting the electron beam from electric field deflection.
4Reliability
If the evaporation chamber and plasma chamber are spaced apart to prevent discharge interference, then electron beam stability improves, but the overall apparatus becomes less compact
Solution Approach 1:
The invention uses a partition wall with a small aperture to divide the chamber into electron beam generation and evaporation regions, achieving functional separation while maintaining physical compactness. The partition wall allows pressure differential maintenance for stable electron beam operation while keeping the overall apparatus volume small through efficient spatial arrangement.
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 configuration enables the generation of high-density ions with improved efficiency and stability, allowing for compact and lightweight ion sources that can produce ions at high energy with controlled vacuum levels and flexible extraction directions.
Implementation Method 1
an electron beam is injected to evaporate metal, or other substance solid at ordinary room temperature
Implementation Method 2
electron collision-ionization in a vapor from an electron beam injected on an evaporation region and from the secondary electrons therein gives rise to a plasma
Implementation Method 3
the interspace between the precursor evaporation chamber and the plasma chamber is compartmentalized with a partitioning wall having a precursor-gas diffusion port for diffusing the vapor (precursor gas) into the plasma chamber
Implementation Method 4
an exhaustion port is provided on the electron beam generating section of the electron beam evaporator, making it so that even with the gas pressure in the precursor evaporation chamber growing high due to exhaustion being carried out, electric discharge in the electron beam generating section will not occur
Data Source
AI summary
Metallic ion source for resolving the issue of not being able to produce high-density ions efficiently with small-scale ion sources in situations where an electron beam injecting scheme is employed as the evaporation source to evaporate a solid, and for producing high-density ions highly efficiently. Designed to be compact and lightweight, the metallic ion source also facilitates selection of the ion extraction direction. The ion source, structured exploiting the characteristic physical property that whether ionization takes place is dependent on the energy of the electron beam, is furnished with a dual evaporation-plasma chamber that inside the same chamber enables a high-speed electron beam, whose ionization efficiency is low, and low-speed electrons generated by electric discharge, whose ionization efficiency is high, to participate independently and simultaneously in, respectively, evaporation of precursor and ionization action.