Aluminum Ion Source Using AlN and Fluorine Gas to Prevent Deposition
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Solution Overview
Problem
Conventional ion sources for aluminum ion generation suffer from the deposition of intermediate products in the reaction chamber, leading to frequent maintenance needs and reduced productivity.
Innovation Solution
An ion source design featuring a cathode electrode, a repeller electrode, a filament, and a gas introduction hole for fluorine-compound gases, where the cathode electrode is heated to generate thermoelectrons that decompose the fluorine-compound gas and react with an aluminum nitride raw-material block, producing aluminum ions without intermediate product deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aluminum nitride and fluorine-based gas are reacted to generate aluminum ion, then ion generation efficiency is improved, but aluminum fluoride deposits in the reaction chamber causing frequent maintenance
Solution Approach 1:
The harmful aluminum fluoride intermediate product is extracted from the reaction chamber through a dedicated discharge path. The reaction chamber is designed with a specific geometry where the aluminum fluoride can be selectively removed through the discharge path while allowing aluminum ions to pass through to the extraction electrode, thus preventing deposition and maintaining continuous operation.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary to control the motion of charged particles. The magnetic field generated by the magnetic field generation unit directs the aluminum fluoride intermediate product toward the discharge path while allowing aluminum ions to reach the extraction electrode, thus mediating the separation of useful product from harmful byproduct.
2Reliability
If aluminum chloride is heated to generate aluminum ion, then ion generation is achieved, but productivity is low
Solution Approach 1:
The patent changes the chemical parameters by using aluminum nitride and fluorine-based gas reaction instead of heating aluminum chloride. This chemical reaction pathway operates at lower temperatures and provides higher reaction efficiency, thus improving productivity while maintaining reliable ion generation capability.
3Productivity
If aluminum fluoride is generated as intermediate product, then aluminum ion generation is enhanced, but deposition in reaction chamber suspends ion generation
Solution Approach 1:
The harmful aluminum fluoride intermediate product is continuously extracted from the reaction chamber through a dedicated discharge path. The reaction chamber is designed with a specific geometry where the aluminum fluoride can be selectively removed through the discharge path while allowing aluminum ions to pass through to the extraction electrode, thus preventing deposition and maintaining continuous operation.
Solution Approach 2:
The patent design ensures continuous removal of aluminum fluoride intermediate product through the discharge path, preventing accumulation and deposition that would suspend ion generation. This continuous extraction mechanism maintains the uninterrupted operation of the ion source, extending the duration of useful action.
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 design results in a durable and long-lasting ion source capable of generating a large amount of aluminum ions stably, with easy replacement of the raw-material block and minimal byproduct accumulation, enhancing the reliability and efficiency of the ion implantation process.
Implementation Method 1
the cathode electrode is heated by the filament through which a current is flowing, and a thermoelectron is emitted from an electron emitting surface of the surface of the cathode electrode
Implementation Method 2
the thermoelectron decomposing the fluorine-compound gas introduced through the gas introduction hole and generating plasma by reciprocally moving between the cathode electrode and the repeller electrode
Implementation Method 3
the positively-charged aluminum ion is generated by reaction of fluorine in the plasma with the raw-material block
Implementation Method 4
the raw-material block is heated to a temperature in a range of 1200 °C to 1700 °C, by heat generation of the cathode electrode
Data Source
Figure 1
Figure 2
Figure 3~4(c)
AI summary
There is provided a long-lasting and durable ion source (10) which can generate a large amount of aluminum ions. A cathode electrode (22) arranged in a chamber (21) is heated by energization of a filament (20) to heat a raw-material block (28) which is arranged sideways on the cathode electrode(22) and includes aluminum nitride. The raw-material block (28) reacts with an introduced fluorine-compound gas, so that aluminum fluoride is emitted. A thermoelectron which is emitted from the cathode electrode (22) and is accelerated reciprocally moves between the cathode electrode (22) and a repeller electrode (23), to decompose an aluminum-fluoride gas and generate an aluminum ion. A long-lasting and durable ion source (10) which can generate a large amount of aluminum ions can be obtained.