Ion Beam System Cold Transfer Member Insulation
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Solution Overview
Problem
Conventional gas field ionization ion sources struggle to generate a high-current, stable ion beam using high-boiling point gases like argon, krypton, and xenon due to difficulties in maintaining low emitter tip temperatures without causing gas condensation, which leads to instability and vacuum system issues.
Innovation Solution
The ion beam system incorporates a cold transfer member with a heat insulating surface to prevent gas condensation, allowing the emitter tip to be cooled to low temperatures without condensation occurring in the cold transfer path, thereby increasing ion emission current and maintaining stable gas pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the emitter tip is cooled to low temperatures to increase ion emission current, then the ion beam current density increases, but gas condensation occurs in the cold transfer path causing instability
Solution Approach 1:
The cold transfer path is segmented into multiple sections with different thermal characteristics. The portion near the emitter tip remains cold for high ion emission, while other sections are thermally isolated or heated to prevent condensation. This segmentation allows different temperature zones coexist in the same transfer path.
Solution Approach 2:
Different sections of the cold transfer path are given different thermal properties. The region close to the emitter tip maintains low temperature to maximize ion emission current, while other regions are equipped with heating elements or thermal insulation to prevent gas condensation. This local differentiation of thermal quality resolves the contradiction between high current and stability.
2Productivity
If high-boiling point gases like argon, krypton, and xenon are used for ion beam generation, then the sputtering effect and processing capability improve, but the required low temperatures cause condensation and vacuum system issues
Solution Approach 1:
The temperature parameters along the gas transfer path are dynamically adjusted based on the local requirements. High-boiling point gases are supplied to the cold emitter tip for efficient ionization and sputtering, while heating elements in other sections maintain temperatures above the condensation point of these gases. This parameter differentiation enables both high productivity and system reliability.
3Quantity of substance
If the emitter tip temperature is reduced to increase molecular density of ionizable gas, then ion beam current increases, but condensation occurs leading to vacuum deterioration
Solution Approach 1:
Heating elements or thermal insulation layers are introduced as intermediary components in the cold transfer path. These intermediaries prevent the cold temperature from propagating to sections where gas condensation would occur, thereby maintaining vacuum quality while allowing high molecular density at the emitter tip for increased ion beam current.
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 configuration enables the formation of ultrafine, high-current ion beams from high-boiling point gases, facilitating high-precision, high-speed processing and ultrahigh resolution observations with improved reliability and stability.
Implementation Method 1
a cold transfer member disposed in said vacuum vessel and transferring cold energy to said emitter tip holder
Implementation Method 2
said cold transfer member has a surface covered with heat insulating material so as to prevent condensation of said gas
Implementation Method 3
gaseous molecules are field-ionized by supplying a gas such as helium gas to a metal emitter tip and applying a high voltage of at least several kilovolts to the emitter tip
Data Source
AI summary
Provided is an ion beam system including a gas field ionization ion source which can obtain a high current sufficient for processing and stabilize an ion beam current. The ion beam system includes a gas field ionization ion source which includes: a vacuum vessel; an emitter tip holder disposed in the vacuum vessel; an emitter tip connected to the emitter tip holder; an extraction electrode opposed to the emitter tip; a gas supply portion for supplying a gas to the emitter tip; and a cold transfer member disposed in the vacuum vessel and transferring cold energy to the emitter tip holder. The cold transfer member has its surface covered with a heat insulating material in order to prevent the gas condensation.