Ion Source Chloride Co-Flow for Arc Chamber Buildup Control
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Solution Overview
Problem
Prolonged use of DMAC in ion sources leads to the buildup of decomposition materials like aluminum carbide, causing nonuniform ion beams, gas flow reduction, and repeller shorting.
Innovation Solution
Introducing a chlorine-containing gas, known as chloride co-flow, into the ion source arc chamber to reduce the buildup of decomposition materials by reacting with decomposition byproducts and maintaining a controlled flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If DMAC is used to generate aluminum ions in the ion source, then aluminum ion beam production is achieved, but decomposition material buildup occurs in the arc chamber
Solution Approach 1:
The patent introduces chlorine-containing gas to react with the decomposition materials (aluminum carbide and other byproducts) formed during DMAC ionization. The chlorine converts the harmful decomposition deposits into volatile aluminum chloride species that can be pumped away, thereby converting the harmful buildup into a removable gaseous form that maintains ion source performance
2Duration of action of moving object
If DMAC is used continuously in the ion source, then sustained aluminum ion beam operation is achieved, but decomposition buildup increases over time
Solution Approach 1:
The patent implements continuous introduction of chlorine-containing gas during DMAC operation. This continuous chemical action prevents decomposition material accumulation by continuously converting deposits into volatile species, thereby maintaining sustained ion beam operation with consistent uniformity over extended periods without interruption for cleaning
3Productivity
If decomposition material builds up in the extraction aperture, then ion beam extraction continues, but beam uniformity deteriorates
Solution Approach 1:
The chlorine-containing gas reacts with decomposition materials forming whiskers in the extraction aperture, converting them into volatile aluminum chloride that can be removed by the vacuum pump. This maintains the extraction aperture clean and preserves ion beam uniformity while continuing productive ion beam extraction
4Reliability
If decomposition material accumulates on the repeller, then repeller function is maintained, but electrical shorting occurs
Solution Approach 1:
The chlorine-containing gas converts decomposition materials accumulating on the repeller into volatile aluminum chloride species that are pumped away. This prevents the buildup that would cause electrical shorting between the repeller and chamber walls, maintaining repeller electrical isolation and function
5Ease of operation
If decomposition material blocks the gas bushing, then gas flow is maintained, but gas flow is reduced or prevented
Solution Approach 1:
The chlorine-containing gas reacts with decomposition materials that would block the gas bushing, converting them into volatile aluminum chloride that flows away with the vacuum pump. This keeps the gas bushing clear and maintains full gas flow rate to the ion source
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 chloride co-flow effectively prevents and reduces the accumulation of decomposition materials, ensuring continuous operation without the need for dedicated cleaning processes, and maintains ion beam uniformity for extended periods.
Implementation Method 1
Introducing a chlorine-containing gas, known as chloride co-flow, into the ion source arc chamber to reduce the buildup of decomposition materials by reacting with decomposition byproducts
Implementation Method 2
The filament emits thermionic electrons, which are accelerated toward and heat the cathode
Implementation Method 3
In some embodiments, a magnetic field is used to further confine the electrons within the arc chamber
Data Source
AI summary
An ion source for generating an ion beam containing aluminum ions is disclosed. The ion source includes a first gas source to introduce an organoaluminium compound into the arc chamber of the ion source. A second gas, different from the first gas, which is a chlorine-containing gas is also introduced to the arc chamber. The chloride co-flow reduces the buildup of decomposition material that occurs within the arc chamber. This buildup may occur at the gas bushing, the extraction aperture or near the repeller. In some embodiments, the second gas is introduced continuously. In other embodiments, the second gas is periodically introduced, based on hours of operation or the measured uniformity of the extracted ion beam. The second gas may be introduced from second gas source or from a vaporizer.