ISO 14707:2021

Overview

ISO 14707:2021 - "Surface chemical analysis - Glow discharge optical emission spectrometry (GD‑OES) - Introduction to use" - provides practical guidelines for performing bulk and depth‑profiling GD‑OES analyses of rigid solid samples. The standard explains the principles of GD‑OES, the required apparatus and peripheral systems (vacuum pumps, gas supply, power supplies, spectrometer and detectors), and offers guidance to regulate instruments and control measuring conditions. It is explicitly limited to rigid solids and does not cover powders, gases or solutions.

Key topics and technical requirements

• Principle of analysis: atomization by cathode sputtering in a glow discharge plasma, excitation/ionization of sputtered atoms and measurement of element‑specific optical emission over time for depth profiles.
• Instrumentation components: glow discharge source (Grimm‑type is used as an example), optical unit (polychromator/monochromator/CCD), photoelectric detectors, power supplies, gas control, vacuum gauge and cooling systems.
• Source parameters and ranges:
  • Anode inner diameter typically 1 mm–10 mm (commonly ~4 mm); anode‑to‑sample spacing ~0.1–0.3 mm.
  • DC operation: discharge current 1 mA–200 mA, voltage 200 V–2 000 V (example conditions given for low‑alloy steel).
  • Gas: usually argon (>99.999%); gas flow/pressure commonly controlled (example ranges 100–500 ml/min, 100–1 500 Pa).
  • RF and pulsed modes are also addressed; measurement of forward/reflected power and RMS/peak voltages is relevant for RF systems.
• Depth profiling capability: layer thicknesses amenable to GD‑OES typically range from a few nanometres to ~100 micrometres; lateral resolution approximates the anode inner diameter.
• Quality control and procedures: verification tests of apparatus, calibration with reference materials, setting of measuring conditions, sputtering‑rate calibration and result quality checks are covered.
• Safety: an informative annex addresses operational safety.

Applications

• Bulk elemental composition analysis of solid materials.
• Depth profiling of thin films, coatings and layered materials (nanometre to ~100 µm thickness).
• Simultaneous multi‑element analysis using polychromators or CCD detectors.
• Instrument development, method validation, laboratory quality assurance and routine materials characterization.

Who should use this standard

• Surface chemical analysts and materials scientists
• Analytical laboratories performing GD‑OES
• Instrument manufacturers and service engineers
• Quality‑control and R&D teams working with coatings, thin films, metals, semiconductors and layered materials

Related standards

Normative references include: ISO 3497 and ISO 5725 series (Parts 1–4) on measurement accuracy, trueness and precision - useful when applying ISO 14707:2021 for calibration and performance assessment.

Keywords: ISO 14707:2021, GD‑OES, glow discharge optical emission spectrometry, surface chemical analysis, depth profiling, bulk analysis, Grimm type, sputtering rate, argon plasma.