1、BS ISO 17973:2016Surface chemical analysis Medium-resolution Augerelectron spectrometers Calibration of energy scales forelemental analysisBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 17973:2016 BRITISH STANDARDNational forewordThis British Standard is the
2、UK implementation of ISO 17973:2016. It supersedes BS ISO 17973:2002 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CII/60, Surface chemical analysis.A list of organizations represented on this committee can be obtained on request to its secretary.Thi
3、s publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 94110 8 ICS 71.040.40 Compliance with a British Standard cannot confer
4、 immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 17973:2016 ISO 2016Surface chemical analysis Medium-resolution
5、 Auger electron spectrometers Calibration of energy scales for elemental analysisAnalyse chimique des surfaces Spectromtres dlectrons Auger rsolution moyenne talonnage des chelles dnergie pour lanalyse lmentaireINTERNATIONAL STANDARDISO17973Second edition2016-09-01Reference numberISO 17973:2016(E)BS
6、 ISO 17973:2016ISO 17973:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll 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, in
7、cluding 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 ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTe
8、l. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 17973:2016ISO 17973:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols and abbreviated terms . 15 Outline of method 26 Energy scale calibration procedures . 36.1 Obtaining re
9、ference samples 36.2 Mounting samples 36.3 Cleaning samples. 36.4 Choosing spectrometer settings for energy calibration 56.5 Operating the instrument 56.6 Measurement of reference peaks 66.7 Determining measured kinetic energies of reference peaks . 76.8 Determining correction of instrument kinetic
10、energy scale . 86.9 Next calibration 9Bibliography .11 ISO 2016 All rights reserved iiiContents PageBS ISO 17973:2016ISO 17973:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Int
11、ernational 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 w
12、ith 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 Directive
13、s, 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
14、 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 declaration
15、s 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 IS
16、Os adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.The committee responsible for this document is Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee SC 7, Electron spectrosco
17、pies. This second edition cancels and replaces the first edition (ISO 17973:2002), of which it constitutes a minor revision, which includes changing “counts per second” to “counts per channel”.iv ISO 2016 All rights reservedBS ISO 17973:2016ISO 17973:2016(E)IntroductionAuger electron spectroscopy (A
18、ES) is used extensively for the surface analysis of materials. Elements in the sample (with the exception of hydrogen and helium) are identified from comparisons of the peak energies and peak shapes, with tabulations of peak energies and data in handbooks of spectra for the different elements. To id
19、entify the peaks, calibration of the energy scale with an uncertainty of 3 eV is generally adequate, and this International Standard is only intended for work at that level of accuracy (for greater accuracy, see ISO 17974).The method for calibrating kinetic energy scales specified in this Internatio
20、nal Standard uses metallic samples of pure copper (Cu) and either aluminium (Al) or gold (Au). It does not include tests for defects in the instrument, since few defects are significant at the level of accuracy concerned.Traditionally, kinetic energies of Auger electrons have been referenced to the
21、vacuum level, and this reference is still used by many analysts. However, the vacuum level is ill-defined and can vary from instrument to instrument over a range of 0,5 eV. Although use of the vacuum level reference procedure will generally not cause ambiguity in elemental identification, it may cau
22、se uncertainty in measurements at high resolution relating to chemical states. Because of this, instruments designed for both Auger electron spectroscopy and X-ray photoelectron spectroscopy reference the kinetic energies to the Fermi level, giving values typically 4,5 eV higher than those reference
23、d to the vacuum level. For the purposes of this International Standard, the user is free to choose the reference appropriate to his or her work. ISO 2016 All rights reserved vBS ISO 17973:2016BS ISO 17973:2016Surface chemical analysis Medium-resolution Auger electron spectrometers Calibration of ene
24、rgy scales for elemental analysis1 ScopeThis International Standard specifies a method for calibrating the kinetic energy scales of Auger electron spectrometers with an uncertainty of 3 eV, for general analytical use in identifying elements at surfaces. In addition, it specifies a method for establi
25、shing a calibration schedule. It is applicable to instruments used in either direct or differential mode, where the resolution is less than or equal to 0,5 % and the modulation amplitude for the differential mode, if used, is 2 eV peak-to-peak. It is applicable to those spectrometers equipped with a
26、n inert gas ion gun or other method for sample cleaning and with an electron gun capable of operating at 4 keV or higher beam energy.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated re
27、ferences, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 18115 (all parts), Surface chemical analysis Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in I
28、SO 18115 apply.4 Symbols and abbreviated termsAES Auger electron spectroscopya measured energy scaling errorb measured zero offset error, in eVEcorrcorrected result for kinetic energy corresponding to given Emeas, in eVEmeasmeasured kinetic energy, in eVEmeas,nmeasured kinetic energy for peak n (see
29、 Table 1), in eVEref,nreference values for kinetic energy position of peak n (see Table 1), in eVFWHM full width at half maximum peak intensity above background, in eVW FWHM of peaknoffset energy, given by average measured kinetic energy for calibration peak minus refer-ence kinetic energy, in eV, f
30、or n = 1, 2, 3, 4 (see Table 1)INTERNATIONAL STANDARD ISO 17973:2016(E) ISO 2016 All rights reserved 1BS ISO 17973:2016ISO 17973:2016(E)Ecorrcorrection added to Emeasafter calibration to provide corrected kinetic energy result energy scale scan rate for analogue systems, in eV/s time constant for an
31、alogue detector electronics, in s5 Outline of methodCalibration of an Auger electron spectrometer using this International Standard is performed by obtaining and preparing copper and gold or aluminium reference foils in order to measure the kinetic energies of selected Auger electron peaks. These re
32、ference materials are chosen as they provide one Auger electron peak in the high energy range, one in the middle range and one at low energies. The samples are cleaned and spectra are recorded in the direct mode, if that is available, or in the differential mode if not. The energies of the peaks are
33、 compared with reference values to provide an energy scale correction. How this correction is implemented depends on the facilities available with the spectrometer. Because this calibration may alter with time, a procedure is defined to enable the calibration to be established at regular intervals.S
34、ee Figure 1 for a flowchart showing the general structure of the work and the sequence of procedures.NOTE The numbers refer to the corresponding subclauses in this International Standard.Figure 1 Flowchart of method Sequence of procedures2 ISO 2016 All rights reservedBS ISO 17973:2016ISO 17973:2016(
35、E)6 Energy scale calibration procedures6.1 Obtaining reference samplesFor the calibration of Auger electron spectrometers providing a high signal-to-noise ratio, as defined below, and able to scan the kinetic energy range up to 2 100 eV, use samples of Cu and Au. For spectrometers with a lower signa
36、l-to-noise ratio or those only able to scan to 2 000 eV, use samples of Cu and Al.If, for the spectrometer used, the counts for the Cu L3VV peak in the direct mode are less than 400 000 counts per channel, or the root mean square noise in the differential spectrum exceeds 0,3 % of the Cu L3VV peak-t
37、o-peak signal, or if the maximum electron beam energy is less than 5 keV, Cu and Al may be used instead of Cu and Au, since the recording of suitable Au data may be time consuming.For instruments with higher signal intensities and for spectrometers able to scan to 2 100 eV, the use of Au could be fo
38、und to be the more convenient and able to provide a calibration over a wider energy range. The requirement for 400 000 counts per channel for the Cu L3VV peak may be relaxed to 100 000 counts per channel if Savitzky and Golay smoothing is available at nine or more points in the smooth.2All samples s
39、hall be polycrystalline and of at least 99,8 % purity metals which, for convenience, are usually in the form of foils typically of an area 10 mm by 10 mm, and from 0,1 mm to 0,2 mm thick.If the samples appear to need cleaning, a short dip in 1 % nitric acid may be used for Cu with subsequent rinsing
40、 in distilled water. If the Cu sample has been stored in the air for more than a few days, the dip in nitric acid will make the sample cleaning (see 6.3) much easier.NOTE Better signal-to-noise ratios are often obtained for 10 keV to 20 keV beam energies, rather than for lower beam energies.6.2 Moun
41、ting samplesMount the samples of Cu and Au or Al on the sample holder or on separate sample holders, as appropriate, using fixing screws or other metallic means to ensure electrical contact. Double-sided adhesive tape shall not be used.6.3 Cleaning samplesAchieve ultra-high vacuum and clean the samp
42、les by ion sputtering to reduce the contamination until the heights of the oxygen and carbon Auger electron peaks are each less than 2 % of the height of the most intense metal peak in each survey spectrum. Record a survey (wide scan) spectrum for each of the samples to ensure that the only signific
43、ant peaks are those of the required pure elements. The quality of vacuum necessary here is such that the oxygen and carbon peak heights shall not exceed 3 % of the heights of the most intense metal peaks by the completion of the procedure in accordance with 6.6 or at the end of the working day, whic
44、hever is the earlier.All relevant procedures of this International Standard should be completed in one working day. If more than one day is required, the cleanness of the samples shall be confirmed at the start of each days work.NOTE Inert gas ion sputtering conditions that have been found suitable
45、for cleaning are 1 min of a 30 A beam of 5 keV argon ions covering 1 cm2of the sample.For examples of direct and differential spectra, see Figure 2. ISO 2016 All rights reserved 3BS ISO 17973:2016ISO 17973:2016(E)a) Cub) Au4 ISO 2016 All rights reservedBS ISO 17973:2016ISO 17973:2016(E)c) AlaDirect
46、spectra.bDifferential spectra.Figure 2 Survey spectra of clean copper, gold and aluminium6.4 Choosing spectrometer settings for energy calibrationSet the spectrometer to acquire spectra in the direct mode, if possible. For spectrometers operating only in differential mode, set the amplitude of the d
47、ifferentiating function to 2 eV peak-to-peak. Choose the remaining spectrometer operating settings for which the energy calibration is required. Repeat the calibration procedure in accordance with 6.4 to 6.6 for each combination of analyser settings of pass energy, retardation ratio, slits, lens set
48、tings, etc., for which a calibration is required. Record the values of these settings in the spectrometer calibration log.NOTE The designs of spectrometers and their circuits vary and a spectrometer calibration made for one combination of lens settings, slits and pass energy will not necessarily be
49、valid for any other combination of lens settings, slits and pass energy. Many spectroscopists make measurements under one optimum combination of analyser settings so that only this combination of settings needs calibration. Any calibration made is only valid for the combination of settings used.6.5 Operating the instrumentIMPORTANT High counting rates3or incorrect detector voltages34can cause peak distortions leading to erroneous peak energy assignments.Operate the instrument in accordance with the manufac
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