ISO/TC 201/SC 2 - General procedures

This document gives guidance on methods of handling, mounting and surface treatment for a biomaterial specimen prior to surface chemical analysis. It is intended for the analyst as an aid in understanding the specialized specimen-handling conditions required for analyses by the following techniques: — X-ray photoelectron spectroscopy (XPS or ESCA); — secondary ion mass spectrometry (SIMS); — Auger electron spectroscopy (AES). The protocols presented are also applicable to other analytical techniques that are sensitive to surface composition, such as: — attenuated total reflectance -Fourier transform infrared spectroscopy (ATR-FTIR); — total reflection X-ray fluorescence (TXRF); — ultraviolet photoelectron spectroscopy (UPS). The influence of vacuum conditions applied and the issue of contamination before and after analysis and implantation, as well as issues related to contamination during analysis, are addressed. Biomaterials covered here are hard and soft specimens such as metals, ceramics, scaffolds and polymers. This document does not cover such viable biological materials as cells, tissues and living organisms. Other related topics not covered in this document include: preparation of specimens for electron or light microscopy.

This document describes methods for measuring lateral resolution and sharpness in imaging surface chemical analysis. It applies to all methods of surface analysis which use a beam to analyse the chemical composition of surfaces under defined settings of an instrument. It applies to scanning instruments, where a finely focused beam is scanned over the sample in a preselected field of view, as well as to full field imaging instruments, where the field of view is simultaneously imaged by a broad beam, an imaging lens system and a pixelated detector. The methods for measuring lateral resolution and sharpness are — the straight edge method; — the narrow line method; — the grating method. This document applies to instruments and methods that provide information on layers with nanometre thicknesses and to surfaces with nanometre‐sized structures and individual nano‐objects.

ISO 20579-4:2018 identifies information to be reported in a datasheet, certificate of analysis, report or other publication regarding the handling of nano-objects in preparation for surface chemical analysis. This information is needed to ensure reliability and reproducibility of analyses needed to advance research and technology using these materials, and for obtaining appropriate understanding of potential nano-object environmental and biological impacts. Such information is in addition to other details associated with specimen synthesis, processing history and characterization, and should become part of the data record (sometimes identified as provenance information) regarding the source of the material and changes that have taken place since it was originated. ISO 20579-4:2018 includes informative annexes that summarize challenges associated with nano-objects that highlight the need for increased documentation and reporting in a material data record (Annex A) and provide examples of methods commonly used to extract particles from a solution for surface chemical analysis (Annex B). An example set of relevant sample data is shown in Annex C. ISO 20579-4:2018 does not define the nature of instrumentation or operating procedures needed to ensure that the analytical measurements described have been appropriately conducted.

ISO/TR 19319:2013 describes: functions and their relevance to lateral resolution: point spread function (PSF), line spread function (LSF), edge spread function (ESF), modulation transfer function (MTF) and contrast transfer function (CTF); experimental methods for the determination of lateral resolution and parameters related to lateral resolution: imaging of a narrow stripe, sharp edge and square-wave gratings; physical factors affecting lateral resolution, analysis area and sample area viewed by the analyser in Auger electron spectroscopy and X-ray photoelectron spectroscopy.

ISO 16242:2011 specifies the minimum level of information to be reported by the analyst following the analysis of a test specimen using Auger electron spectroscopy (AES). It includes information that is to be recorded on or in the analytical record.

ISO 16243:2011 specifies the minimum level of information to be reported by the analyst following the analysis of a test specimen using X‑ray photoelectron spectroscopy (XPS). It includes information that is to be recorded on or in the analytical record.

ISO/TR 16268:2009 specifies a procedure for the certification of the areic dose of an ion-implanted analyte element of atomic number larger than that of silicon retained in a working reference material (WoRM) intended for surface-analytical use. The WoRM is in the form of a polished (or similarly smooth-faced) wafer (also referred to as the host), of uniform composition and nominal diameter 50 mm or more, that has been ion-implanted with nominally one isotope of a chemical element (also referred to as the analyte), not already present in the host, to a nominal areic dose normally within the range 1016 atoms/cm2 to 1013 atoms/cm2 (i.e. the range of primary interest in semiconductor technology). The areic dose of the ion-implanted analyte retained in the WoRM wafer is certified against the areic dose of the same analyte retained in an ion-implanted silicon wafer having the status of a (preferably certified) secondary reference material (SeRM). Information is provided on the concept and the procedure for certification of the WoRM. There is also a description of the requirements for the reference materials, the comparative measurements and the actual certification. Supporting information on ion implantation, ion-implantation dosimetry, wavelength-dispersive X‑ray fluorescence spectroscopy and non-certified substitutes for unobtainable SeRMs is provided in four annexes. Sources and magnitudes of uncertainties arising in the certification process are detailed in a fifth annex.

ISO 18117:2009 gives guidance on the handling of and the containers for specimens submitted for surface chemical analysis. It is intended for the user of surface analysis services as an aid in understanding the special sample handling requirements of surface chemical analysis techniques, particularly the following: Auger electron spectroscopy (AES), secondary-ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS or ESCA). The protocols presented may also be applicable to other analytical techniques, such as TXRF, that are sensitive to surface composition. In particular instances, with particular specimens, further precautions may be necessary.

ISO 18116:2005 gives guidance on methods of mounting and surface treatment for a specimen about to undergo surface chemical analysis. It is intended for the analyst as an aid in understanding the specialized specimen-handling conditions required for analyses by techniques such as Auger electron spectroscopy, secondary-ion mass spectrometry, and X-ray photoelectron spectroscopy.

ISO 18516:2006 describes three methods for measuring the lateral resolution achievable in Auger electron spectrometers and X-ray photoelectron spectrometers under defined settings. The straight-edge method is suitable for instruments where the lateral resolution is expected to be larger than 1 micrometre. The grid method is suitable if the lateral resolution is expected to be less than 1 micrometre but more than 20 nm. The gold-island method is suitable for instruments where the lateral resolution is expected to be smaller than 50 nm. Annexes A, B and C provide illustrative examples of the measurement of lateral resolution.

ISO/TR 19319:2003 provides information for measuring (1) the lateral resolution, (2) the analysis area, and (3) the sample area viewed by the analyser in Auger electron spectroscopy and X-ray photoelectron spectroscopy.