ISO 20903:2019

Overview

ISO 20903:2019 specifies what information must be reported and which methods are appropriate when determining peak intensities from Auger electron spectroscopy (AES) and X‑ray photoelectron spectroscopy (XPS) spectra. The standard covers procedures for measuring peak heights and areas, selecting and subtracting inelastic backgrounds, treating overlapping peaks, estimating uncertainties, and reporting the analytical results so they are reproducible and transparent.

Key topics and requirements

• Scope and reporting: Specifies mandatory information to include in analytical reports based on AES/XPS peak-intensity measurements (methods, parameters, uncertainties).
• Background selection and subtraction: Discusses common inelastic-background models - linear, Shirley (integral), and physically based Tougaard and Werner backgrounds - and guidance on choosing endpoints and energy ranges (typical endpoint separations such as ≥10 eV above a peak are discussed).
• Peak measurement methods:
  • Peak height: direct readout, baseline-corrected height, or height from fitted analytical shapes (Gaussian, Lorentzian, or mixed).
  • Peak area: integrated area after background subtraction; guidance on avoiding smoothing for area determination.
  • Computer-assisted fitting: treatment of overlapping peaks and use of fitting software.
• Auger differential spectra: Specific methods for measuring differential AES intensities and associated uncertainty treatment.
• Uncertainty and precision: Factors affecting uncertainty (endpoint selection, baseline averaging, instrumental effects) and references to methods for estimating standard deviation of peak area.
• Data handling practices: Averaging channels to define baselines, limits on smoothing (Savitzky–Golay guidance), and documenting software/algorithms used.
• Informative annexes: Instrumental effects on intensities and suggested integration limits for XPS peaks.

Applications and who uses it

ISO 20903:2019 is essential for professionals performing surface chemical analysis where quantitative or semi-quantitative AES/XPS results are required:

• Surface scientists and analytical chemists characterizing thin films, coatings, corrosion layers, contamination, and semiconductor surfaces.
• Quality control and R&D laboratories that need standardized reporting for traceability and comparability.
• Instrument manufacturers and software developers implementing peak-intensity algorithms.
• Standards bodies and auditors assessing conformity of surface analysis reports.

Related standards

• ISO 18115-1 (Surface chemical analysis - Vocabulary)
• ISO/TR 18392 (referenced guidance on background subtraction and spectral processing)

Keywords: ISO 20903:2019, AES, XPS, peak intensities, peak area, background subtraction, Shirley background, Tougaard background, peak fitting, surface chemical analysis, uncertainty.