Composite Metal-Fluoride Ion Source for Higher Metal Beam Current
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Solution Overview
Problem
Current ion sources for semiconductor implantation face challenges in generating high ion current for metallic species due to low melting points and high vapor pressures of materials like Ga, Ge, and Al, which require complex handling and result in modest ion current output.
Innovation Solution
An ion source using a charge mixture of elemental metal and a heterogeneous metal fluoride compound is employed, which reduces vapor pressure and increases ion beam current by forming volatile sub-fluorides when heated, allowing for improved control and stability in metal ion generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pure metal dopants are used in a vaporizer with passive heating, then the ion source can generate metallic vapor, but the vapor output is low and ion beam currents are limited
Solution Approach 1:
The patent changes the chemical composition parameters by introducing metal fluoride compounds (e.g., GaF3, InF3, AlF3) mixed with elemental metal (e.g., Ga, In, Al) in the charge source. This compositional parameter change enables the formation of volatile sub-fluorides at lower temperatures, dramatically increasing metal vapor output and subsequent ion beam current while maintaining operational feasibility
Solution Approach 2:
The patent employs a composite charge material system consisting of elemental metal combined with metal fluoride compounds. This composite approach leverages the volatile sub-fluoride formation mechanism to enhance vapor pressure and ion production, resolving the contradiction between limited vapor output and the need for high ion beam current
2Ease of manufacture
If metallic species with low melting points are used, then the material is easier to vaporize, but the high vapor pressure makes handling difficult
Solution Approach 1:
The patent introduces metal fluoride compounds as intermediary substances that facilitate controlled vaporization. These fluorides form volatile sub-fluorides that act as intermediaries between the solid charge material and the metal vapor, enabling easier and more controlled vaporization while reducing direct handling of high-vapor-pressure metals
3Quantity of substance
If the charge source temperature is increased to generate sufficient metallic vapor, then vapor output improves, but control and stability become more difficult
Solution Approach 1:
The patent changes the chemical reaction pathway by introducing metal fluorides that form volatile sub-fluorides at lower temperatures. This chemical parameter change allows achieving sufficient metal vapor output at reduced temperatures, improving charge source control and operational stability while maintaining high vapor production
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 enhances metal ion beam current and stability, enabling more efficient ion implantation by reducing vapor pressure and increasing the formation of volatile sub-fluorides, thus overcoming the limitations of pure metal-based ion sources.
Implementation Method 1
heating the charge mixture to an operating temperature, wherein the charge source generates a metal vapor comprising at least one metal sub-fluoride species
Implementation Method 2
generating metal ions in an ion chamber of the metal ion source, the metal ions being derived from the metal vapor
Data Source
AI summary
An ion source is provided. The ion source may include an ion chamber to generate an ion beam comprising a metal ion species; and a charge source, coupled to deliver a metal vapor to the ion chamber, the charge source including a charge mixture. The charge mixture may include a first portion, comprising an elemental metal; and a second portion, comprising a heterogeneous metal fluoride compound.