Overview
ISO 14606:2022 - "Surface chemical analysis - Sputter depth profiling - Optimization using layered systems as reference materials" provides guidance and requirements to optimize sputter depth profiling for surface chemical analysis. It specifies how to use single-layered and multilayered reference materials to achieve optimum depth resolution as a function of instrument settings in Auger electron spectroscopy (AES), X‑ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The standard is explicit that special multilayer systems such as delta-doped layers are out of scope.
Key topics and requirements
- Optimization approach: Use of layered reference systems (single and multilayer) to evaluate and set instrument parameters for best depth resolution.
- Instrument families covered: AES, XPS, SIMS - including probing and sputtering parameter considerations for each technique.
- Critical parameters:
- Probing: electron/photon/primary ion energy, beam/current or source power, analysis area, emission angle.
- Sputtering: ion species, ion energy (typical range 0.1–25 keV in the standard), ion beam current (examples 1–10 nA), incidence angle, sputtered area and rastering.
- Measurement and metrics:
- Determination of average sputtering rate and the depth resolution (Δz) at an ideally sharp interface.
- Guidance on measuring depth resolution using layered references, and caveats for SIMS when matrix effects differ.
- Procedures and alignment:
- Practical procedures to align a sputtered crater with a smaller analysis area (including manufacturer-provided alignment tools).
- Stepwise optimization of parameter settings to balance analysis sensitivity versus depth resolution.
- Supporting material: Informative annexes on factors influencing depth resolution, typical reference single- and multilayer systems, and uses of multilayered systems.
Applications and users
ISO 14606:2022 is practical for:
- Surface analysts and lab technicians performing sputter depth profiling in AES, XPS and SIMS.
- Instrument manufacturers validating and demonstrating performance.
- Materials scientists and semiconductor engineers characterizing multilayer devices (e.g., optical/heterostructure devices) and coatings.
- Quality and metrology labs assessing depth profiling reproducibility and instrument settings.
Practical uses include optimizing ion beam conditions to reduce sputter-induced roughening, evaluating sample drift and crater geometry effects, and choosing suitable reference materials for method development.
Related standards
- Normative reference: ISO 18115-1 (Surface chemical analysis - Vocabulary).
- Developed by ISO/TC 201 (Surface chemical analysis) - useful alongside other ISO guidance on surface analysis and metrology.
Keywords: ISO 14606:2022, sputter depth profiling, surface chemical analysis, depth resolution, reference materials, AES, XPS, SIMS, ion sputtering.
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