Ion angle distribution measurement with a planar retarding field analyzer.

Area of Science:

• Plasma Physics
• Surface Science
• Analytical Instrumentation

Background:

• Understanding plasma-ion interactions with surfaces is crucial for materials processing and device fabrication.
• Accurate measurement of ion angular distribution is essential for controlling surface modification.
• Existing techniques may lack the precision or adaptability for detailed angular analysis.

Purpose of the Study:

• To introduce a new technique for measuring the angular distribution of plasma ions bombarding a substrate.
• To develop and validate an analytical theory for quantifying ion current based on incident angle and apparatus geometry.
• To demonstrate the capability of measuring ion energy distributions as a function of ion angle with high resolution.

Main Methods:

• Utilized a planar retarding field analyzer with a variable effective aperture aspect ratio.
• Developed analytical theory relating ion current to incident angle, ion energy, aperture geometry, and aspect ratio.
• Derived mathematical theory and discussed numerical solutions for data interpretation.

Main Results:

• Successfully controlled the angular spread of ions detected by varying the analyzer's aperture aspect ratio.
• Presented a theoretical framework to define ion current as a function of multiple parameters.
• Achieved measurement resolution as low as 3° for ion energy distributions versus ion angle.

Conclusions:

• The presented technique offers a precise method for analyzing plasma ion angular distributions.
• The developed analytical theory provides a robust foundation for interpreting measurement data.
• This advancement facilitates detailed characterization of ion-substrate interactions, crucial for plasma-based technologies.