Insertable Target Holder for Ion Source Dopant Containment
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Solution Overview
Problem
Ion sources using indirectly heated cathodes face issues with solid dopant materials having low melting points, as they tend to melt, drip, and degrade the arc chamber, leading to contamination and reduced beam current, while ceramic dopants generate less beam current and are not ideal for high-temperature environments.
Innovation Solution
An ion source with an insertable target holder that contains the solid dopant material within a pocket, allowing it to be moved in and out of the arc chamber, maintaining containment and preventing degradation, and featuring a sleeve to cover the open top, ensuring the dopant remains within the holder even when melted, and an actuator to control its position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid dopant materials with low melting points are used in an IHC ion source, then dopant beam current is increased, but the materials melt, drip, and degrade the arc chamber
Solution Approach 1:
The target holder is divided into distinct functional sections: a pocket to contain the dopant material, a body to support the pocket, and a stem for actuator attachment. This segmentation allows the dopant to be isolated in a protected environment while maintaining the structural integrity of the holder itself.
Solution Approach 2:
The target holder acts as an intermediary component between the dopant material and the arc chamber. It provides a controlled interface that allows the dopant to be positioned within the arc chamber for ion generation while preventing direct contact between the melting dopant and the arc chamber walls, thus protecting the chamber from degradation.
2Reliability
If ceramic dopant materials are used to prevent arc chamber degradation, then arc chamber integrity is maintained, but dopant beam current is reduced
Solution Approach 1:
The target holder serves as a protective intermediary that enables the use of low-melting-point dopant materials without directly exposing them to the arc chamber environment. This mediator allows pure metals to be used as dopants while preventing the harmful effects that would otherwise necessitate the use of less effective ceramic materials.
3Productivity
If the target holder is inserted into the arc chamber, then dopant beam current is increased, but contamination of the arc chamber occurs
Solution Approach 1:
The dopant material is extracted from direct contact with the arc chamber environment by containing it within the sealed pocket of the target holder. This extraction eliminates the source of contamination while still allowing the dopant to function within the arc chamber when the holder is positioned appropriately.
Solution Approach 2:
The sealed pocket structure acts as an intermediary barrier between the dopant material and the arc chamber atmosphere, preventing contamination while enabling the dopant to be effectively utilized for ion generation when needed.
4Ease of operation
If the target holder is made open-topped for easy loading, then ease of operation is improved, but dopant material spills when melted
Solution Approach 1:
The target holder is segmented into a pocket portion for dopant containment and a stem portion for actuator attachment and positioning. This segmentation allows the pocket to be designed with an open top for easy loading while the overall structure provides reliable containment when inserted into the arc chamber.
Solution Approach 2:
The target holder is designed as a dynamic component that can be positioned in different states: open-topped during loading operations and closed/covered during operation within the arc chamber. This dynamic configuration allows the holder to adapt to different operational requirements, providing ease of loading when needed and reliable containment when in use.
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 solution allows for increased dopant beam current and prevents contamination, enabling the use of pure metals as sputter targets, enhancing beam current by up to 75% and allowing for faster tune times and easier dopant material handling, while maintaining arc chamber cleanliness for other processes.
Implementation Method 1
In the high-temperature environment of an IHC ion source, metal sputter targets are prone to melting
Implementation Method 2
the target holder is oriented in the arc chamber so that gravity retains the dopant material in the target holder
Implementation Method 3
The filament emits thermionic electrons, which are accelerated toward and heat the cathode, in turn causing the cathode to emit electrons into the arc chamber
Implementation Method 4
An extraction aperture is disposed along one of these sides, proximate the center of the arc chamber, through which the ions created in the arc chamber may be extracted
Data Source
AI summary
An ion source with an insertable target holder for holding a solid dopant material is disclosed. The insertable target holder includes a pocket or cavity into which the solid dopant material is disposed. When the solid dopant material melts, it remains contained within the pocket, thus not damaging or degrading the arc chamber. Additionally, the target holder can be moved from one or more positions where the pocket is at least partially in the arc chamber to one or more positions where the pocket is entirely outside the arc chamber. In certain embodiments, a sleeve may be used to cover at least a portion of the open top of the pocket.