Ion Source Consumable Structure for Low Vapor Pressure Dopants
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Solution Overview
Problem
Ion implantation systems face challenges with dopant source materials having low vapor pressure, requiring high temperatures for efficient delivery, which leads to decomposition and control issues, limiting the use of antimony, indium, and gallium dopant species due to the scarcity of high vapor pressure precursors.
Innovation Solution
The use of a consumable structure in the ion source chamber that reacts with a reactive gas to release dopant species in gaseous form, enabling the generation of ionized dopant species from low vapor pressure materials like antimony, indium, and gallium, and employing specific precursor compositions and co-flow gases to improve ion source life and beam current characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperatures are used to deliver low vapor pressure dopant source materials, then delivery efficiency is improved, but decomposition and side reactions increase
Solution Approach 1:
The invention changes the physical state of the dopant source material from solid to liquid, which fundamentally alters the vapor pressure characteristics. Liquid dopant sources exhibit significantly higher vapor pressure compared to solid sources, enabling efficient dopant delivery at lower temperatures. This parameter change resolves the contradiction by allowing high productivity without the harmful high temperatures that cause decomposition and poor process control.
2Productivity
If high temperatures are used for dopant source material delivery, then vaporization efficiency is improved, but control valve functionality deteriorates
Solution Approach 1:
By changing the dopant source material from solid to liquid state, the invention achieves high vaporization efficiency without requiring high temperatures. The liquid state provides inherently higher vapor pressure, enabling effective vaporization at moderate temperatures where control valves can function properly. This resolves the contradiction between vaporization efficiency and ease of operation.
3Stability of the object's composition
If solid dopant source materials with low vapor pressure are used, then material stability is improved, but delivery efficiency deteriorates
Solution Approach 1:
The invention changes the physical state parameter from solid to liquid, which dramatically increases vapor pressure and thereby improves dopant delivery efficiency. Liquid dopant sources provide both adequate stability and high delivery efficiency, resolving the contradiction between material stability and productivity. The liquid state maintains compositional stability while enabling efficient vapor-phase transport of dopant atoms.
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 approach allows for efficient utilization of low vapor pressure dopant source materials, enhancing ion source life and beam current performance while minimizing decomposition and safety hazards, and expanding the range of usable dopant species in ion implantation processes.
Implementation Method 1
a consumable structure in or associated with the ion source chamber, the consumable structure comprising a solid dopant source material susceptible to reaction with a reactive gas for release of dopant in gaseous form to the ion source chamber
Implementation Method 2
release of dopant in gaseous form to the ion source chamber for ionization therein to form ionized dopant species
Data Source
AI summary
An ion source apparatus which generates dopant species in a manner enabling low vapor pressure dopant source materials to be employed. The ion source apparatus (10), comprising: an ion source chamber (12); and a consumable structure in or associated with the ion source chamber (12), said consumable structure comprising a solid dopant source material susceptible to reaction with a reactive gas for release of dopant in gaseous form to the ion source chamber. For example, the consumable structure is a dopant gas feed line (14) comprising a pipe or conduit having an interior layer formed of a solid dopant source material.