2-D nanometer thickness mapping applying a reduced bias soft X-ray NEXAFS approach

Area of Science:

• Materials Science
• Surface Science
• Spectroscopy

Background:

• Accurate sample thickness measurement is crucial for material characterization.
• Traditional methods may have limitations in spatial resolution or accuracy.
• Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy offers elemental and chemical state sensitivity.

Purpose of the Study:

• To develop and validate a 2-D thickness mapping technique for thin films using NEXAFS.
• To achieve nanometer accuracy in thickness measurements.
• To analyze and mitigate error sources in NEXAFS-based thickness mapping.

Main Methods:

• Utilized a compact near-edge X-ray absorption fine structure (NEXAFS) spectroscopy setup.
• Coupled NEXAFS with a scanning system to acquire 2-D spectral data.
• Applied and compared different data processing methods, including an "average one" approach, to retrieve thickness values.

Main Results:

• Successfully generated a 2-D thickness map of a TiO2 (anatase) film on a SiN membrane with nanometer accuracy.
• Demonstrated that an averaging procedure effectively reduces errors from signal bias.
• Validated NEXAFS-derived thickness measurements against scanning electron microscopy (SEM) data.

Conclusions:

• The presented NEXAFS-based method provides accurate 2-D thickness mapping of thin films.
• The "average one" data processing approach enhances measurement reliability.
• This technique is a valuable tool for nanoscale material characterization and quality control.