Analysis of solids with a secondary-neutral microprobe based on electron-gas post-ionization

Area of Science:

• Surface Science
• Analytical Chemistry
• Materials Science

Background:

• Secondary-Neutral Mass Spectrometry (SNMS) is a powerful surface analysis technique.
• Existing SNMS methods face limitations in detection sensitivity and lateral resolution.
• Advancements are needed to improve the performance of SNMS instruments for detailed material characterization.

Purpose of the Study:

• To develop a novel secondary-neutral microprobe with enhanced detection sensitivity and lateral resolution.
• To combine high post-ionization efficiency with a high-transmission magnetic mass spectrometer.
• To demonstrate the capabilities of the new instrument for surface analysis.

Main Methods:

• Development of a new secondary-neutral microprobe.
• Utilizing an electron-gas SNMS approach with an rf-plasma for high post-ionization efficiency (alpha(0) ~ 10(-2)).
• Employing a 20 keV Ga(+) ion beam from a liquid-metal ion source (LMIS) for sputter excitation and lateral resolution (1 µm spot size).

Main Results:

• Achieved high secondary-neutral intensities up to 10(9) cps with Ar(+) ion bombardment (1 keV, 1 mA/cm(2)).
• Demonstrated a detection sensitivity of ≤ 10(-2) in the microprobe operation mode.
• Successfully recorded mass spectra and laterally resolved images, showcasing the instrument's analytical capacity.

Conclusions:

• The newly developed secondary-neutral microprobe significantly improves detection sensitivity and lateral resolution in SNMS.
• The instrument's design, combining high post-ionization efficiency and a focused ion beam, enables advanced surface analysis.
• This microprobe represents a valuable tool for detailed surface characterization and elemental analysis.