End-Mounted Sputter Target Ion Source for Longer Solid Dopant Life
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Solution Overview
Problem
Existing indirectly heated cathode (IHC) ion sources face challenges in using solid feed materials due to issues with vaporizers operating at high temperatures and heat shielding, as well as limitations with solid sputter targets having low melting temperatures and limited life.
Innovation Solution
The ion source design includes a sputter target made of a dopant-containing material located at the end opposite the cathode, which can be a solid material with a higher melting point than the dopant species, allowing for a larger solid sputter target and improved operational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a solid sputter target is disposed within the arc chamber, then dopant species can be supplied in solid form, but the target has limited life due to low melting temperatures and size constraints
Solution Approach 1:
The patent changes the melting point parameter of the sputter target material by selecting materials with melting points above 1200°C (such as tungsten, molybdenum, or refractory alloys), which allows the target to withstand higher operating temperatures and extends its operational life while maintaining solid dopant supply capability
Solution Approach 2:
The patent employs composite material structures where the sputter target is made of refractory materials that can be combined with dopant-containing materials, creating a composite structure that provides both high thermal stability and dopant supply functionality, thereby extending target life
2Quantity of substance
If a vaporizer is used to supply solid feed material, then dopant species can be introduced into the arc chamber, but vaporizers are difficult to operate at temperatures greater than 1200 Celsius with heat shielding and condensation issues
Solution Approach 1:
The patent extracts the vaporizer component from the system entirely and replaces it with a direct solid sputter target configuration disposed within the arc chamber, eliminating the operational difficulties associated with high-temperature vaporizer operation, heat shielding requirements, and condensation issues in connecting tubes
Solution Approach 2:
The patent introduces a refractory sputter target as an intermediary material that directly supplies dopant species to the plasma without requiring vaporization, thereby mediating between the solid dopant source and the plasma environment while avoiding the temperature and condensation problems of traditional vaporizer systems
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 enables the use of larger solid sputter targets with extended life, overcoming the limitations of low melting temperatures and heat shielding issues, while maintaining efficient ion beam generation.
Implementation Method 1
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 2
The ion source may include an indirectly heated cathode and the sputter target may be disposed on the end opposite the cathode
Data Source
AI summary
An ion source with a sputter target located at the end of the ion source is disclosed. The ion source may include an indirectly heated cathode and the sputter target may be disposed on the end opposite the cathode. The ion source may contain one or more side electrodes, wherein at least one of these electrodes is electrically biased relative to the arc chamber. In one embodiment, the second end of the ion source is made of a dopant containing material and serves as the sputter target. In another embodiment, there is an opening in the second end, and an insert is disposed in this opening. The insert is made of a dopant containing material and serves as the sputter target.