Refined Appearance Potential Mass Spectrometry for High Precision Radical Density Quantification in Plasma

Area of Science:

• Plasma physics and chemistry
• Surface science and engineering

Background:

• Accurate quantification of radical density is crucial for understanding complex plasma reaction chemistry, particularly in plasma processing.
• Conventional appearance potential mass spectrometry (APMS) methods can introduce significant errors due to undefined fitting ranges.

Purpose of the Study:

• To develop a novel APMS approach that minimizes errors by eliminating the fitting process.
• To enhance the precision of plasma diagnosis and contribute to a clearer understanding of plasma etching processes.

Main Methods:

• A new appearance potential mass spectrometry (APMS) technique was developed, designed to circumvent the fitting process inherent in conventional methods.
• Neutral densities in Helium (He) plasma were measured using both the conventional APMS and the newly proposed method.

Main Results:

• The proposed APMS quantification approach demonstrated higher accuracy in determining neutral densities compared to the conventional method.
• Validation against neutral densities calculated using the ideal gas equation confirmed the improved accuracy of the new method.

Conclusions:

• The novel APMS method offers a more precise and reliable approach for quantifying radical density in plasma environments.
• This advancement is expected to significantly improve the accuracy of plasma diagnostics and deepen the understanding of plasma-based material processing techniques.