ISO 18118:2015

INTERNATIONAL ISO
STANDARD 18118
Second edition
2015-04-01
Surface chemical analysis — Auger
electron spectroscopy and X-ray
photoelectron spectroscopy —
Guide to the use of experimentally
determined relative sensitivity
factors for the quantitative analysis of
homogeneous materials
Analyse chimique des surfaces — Spectroscopie des électrons Auger
et spectroscopie de photoélectrons — Lignes directrices pour
l’utilisation de facteurs expérimentaux de sensibilité relative pour
l’analyse quantitative de matériaux homogènes
Reference number
©
ISO 2015
© ISO 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 General information . 3
6 Measurement conditions . 4
6.1 General . 4
6.2 Excitation source . 4
6.3 Energy resolution . 4
6.4 Energy step and scan rate. 4
6.5 Signal intensity . . 4
6.6 Gain and time constant (for AES instruments with analogue detection systems) . 4
6.7 Modulation to generate a derivative spectrum . 4
7 Data-analysis procedures . 5
8 Intensity-energy response function . 5
9 Determination of chemical composition using relative sensitivity factors .5
9.1 Calculation of chemical composition . 5
9.1.1 General. 5
9.1.2 Composition determined from elemental relative sensitivity factors . 6
9.1.3 Composition determined from atomic relative sensitivity factors or average
matrix relative sensitivity factors. 6
9.2 Uncertainties in calculated compositions . 6
Annex A (normative) Formulae for relative sensitivity factors . 7
Annex B (informative) Information on uncertainty of the analytical results .20
Bibliography .23
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/TC 201, Surface chemical analysis, Subcommittee
SC 7, Electron spectroscopies.
This second edition cancels and replaces the first edition (ISO 18118:2004), which has been
technically revised.
iv © ISO 2015 – All rights reserved

Introduction
Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) are surface-analytical
techniques that are sensitive to the composition in the surface region of a material to depths of, typically,
a few nanometres (nm). Both techniques yield a surface-weighted signal, averaged over the analysis
volume. Most samples have compositional variations, both laterally and with depth, and quantification
is often performed with approximate methods since it can be difficult to determine the magnitude of
any compositional variations and the distance scale over which they might occur. The simplest sample
for analysis is one that is homogeneous. Although this situation occurs infrequently, it is often assumed,
for simplicity in the analysis, that the sample material of interest is homogeneous. This International
Standard provides guidance on the measurement and use of experimentally determined relative
sensitivity factors for the quantitative analysis of homogeneous materials by AES and XPS.
INTERNATIONAL STANDARD ISO 18118:2015(E)
Surface chemical analysis — Auger electron spectroscopy
and X-ray photoelectron spectroscopy — Guide to the use
of experimentally determined relative sensitivity factors
for the quantitative analysis of homogeneous materials
1 Scope
This International Standard gives guidance on the measurement and use of experimentally determined
relative sensitivity factors for the quantitative analysis of homogeneous materials by Auger electron
spectroscopy and X-ray photoelectron spectroscopy.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 18115, Surface chemical analysis — Vocabulary
ISO 21270, Surface chemical analysis — X-ray photoelectron and Auger electron spectrometers — Linearity
of intensity scale
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18115 and the following apply.
3.1
absolute elemental sensitivity factor
coefficient for an element by which the measured intensity for that element is divided to yield the atomic
concentration or atomic fraction of the element present in the sample
Note 1 to entry: The choice of use of atomic concentration or atomic fraction should be made clear.
Note 2 to entry: The type of sensitivity factor used should be appropriate for the equations used in the quantification
process and for the type of sample analysed, for example, of homogeneous samples or segregated layers.
Note 3 to entry: The source of the sensitivity factors should be given in order that the correct matrix factors or
other parameters have been used.
Note 4 to entry: Sensitivity factors depend on parameters of the excitation source, the spectrometer, and the
orientation of the sample to these parts of the instrument. Sensitivity factors also depend on the matrix being
analysed and in SIMS, this has a dominating influence.
[SOURCE: ISO 18115:2013, modified]
3.2
relative elemental sensitivity factor
coefficient proportional to the absolute elemental sensitivity factor (3.1), where the constant of
proportionality is chosen such that the value for a selected element and transition is unity
Note 1 to entry: Elements and transitions commonly used are C 1s or F 1s for XPS and Ag M VV for AES.
4,5
Note 2 to entry: The type of sensitivity factor used should be appropriate for the analysis, for example, of
homogeneous samples or segregated layers.
Note 3 to entry: The source of the sensitivity factors should be given in order that the correct matrix factors or
other parameters have been used.
Note 4 to entry: Sensitivity factors depend on parameters of the excitation source, the spectrometer, and the
orientation of the sample to these parts of the instrument. Sensitivity factors also depend on the matrix being
analysed and in SIMS, this has a dominating influence.
[SOURCE: ISO 18115:2013]
3.3
average matrix relative sensitivity factor
coefficient proportional to the intensity calculated for a pure element in an average matrix with which
the measured intensity for that element is divided in calculations to yield the atomic concentration or
atomic fraction of the element present in the sample
Note 1 to entry: The choice of use of atomic concentration or atomic fraction should be made clear.
Note 2 to entry: The type of sensitivity factor used should be appropriate for the equations used in the quantification
process and for the type of sample analysed, for example, of homogeneous samples or segregated layers.
Note 3 to entry: The source of the sensitivity factors should be given. Matrix factors are taken to be unity for
average matrix relative sensitivity factors.
Note 4 to entry: Sensitivity factors depend on parameters of the excitation source, the spectrometer, and the
orientation of the sample to these parts of the instrument.
[SOURCE: ISO 18115:2013, modified]
3.4
pure-element relative sensitivity factor
coefficient proportional to the intensity measured for a pure sample of an element with which the
measured intensity for that element is divided in calculations to yield the atomic concentration or atomic
fraction of the element present in the sample
Note 1 to entry: The choice of use of atomic concentration or atomic fraction should be made clear.
Note 2 to entry: The type of sensitivity factor used should be appropriate for the equations used in the quantification
process and for the type of sample analysed, for example, of homogeneous samples or segregated layers.
Note 3 to entry: The source of the sensitivity factors should be given in order that the correct matrix factors or
other parameters have been used. Matrix factors are significant and should be used with pure-element relative
sensitivity factors.
Note 4 to entry: Sensitivity factors depend on parameters of the excitation source, the spectrometer, and the
orientation of the sample to
...