1、BRITISH STANDARD BS ISO 24236:2005 Surface chemical analysis Auger electron spectroscopy Repeatability and constancy of intensity scale ICS 71.040.40 BS ISO 24236:2005 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 12 May 2005 BSI 12 May 200
2、5 ISBN 0 580 45967 5 National foreword This British Standard reproduces verbatim ISO 24236:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CII/60, Surface chemical analysis, which has the responsibility to: A list of or
3、ganizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence I
4、ndex”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself c
5、onfer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promu
6、lgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 14, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued.
7、 Amendments issued since publication Amd. No. Date Comments Reference number ISO 24236:2005(E) OSI 5002INTERNATIONAL STANDARD ISO 24236 First edition 2005-04-15 Surface chemical analysis Auger electron spectroscopy Repeatability and constancy of intensity scale Analyse chimique des surfaces Spectros
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13、 Allr ithgsr esedevrBSISO24236:2005IS:63242 O5002(E) I SO 5002 All irthgs ersedevr iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Symbols . 1 3 Outline of method . 2 4 Method for evaluating the repeatability and constancy of the intensity scale. 2 4.1 Obtaining the reference sample 2 4.2 Mo
14、unting the sample 3 4.3 Cleaning the sample . 3 4.4 Choosing the spectrometer settings for which intensity stability is to be determined 4 4.5 Operating the instrument . 5 4.6 Options for initial or subsequent evaluation measurements. 5 4.7 Measurements for the intensity and repeatability . 5 4.8 Ca
15、lculating the peak intensities, intensity ratios and uncertainties . 7 4.9 Procedure for the regular evaluation of the constancy of the intensity scale . 8 4.10 Next evaluation 9 Annex A (informative) Example of calculations and measurements of the intensity repeatability for a commercial Auger elec
16、tron spectrometer. 10 Bibliography . 14 BSISO24236:2005IS:63242 O5002(E) iv I SO 5002 All irthgs ersedevrForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is norm
17、ally 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 t
18、he work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare
19、 International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some
20、 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. ISO 24236 was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee SC 7, X-ray photoelectron spectroscopy. BSISO24236
21、:2005IS:63242 O5002(E) I SO 5002 All irthgs ersedevr vIntroduction Auger electron spectroscopy (AES) 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 measured kinetic energies of emitt
22、ed Auger electrons with tabulations of those energies for the different elements. Information on the quantities of such elements can be derived from the measured Auger electron intensities. Calculation of the quantities present may then be made using formulae and relative sensitivity factors provide
23、d by the spectrometer manufacturer. It is important that the sensitivity factors are appropriate for the instrument and this will generally be the case directly after installation of the equipment or calibration of the instrument intensity/energy response function by an appropriate organization. The
24、re are two important instrumental contributions to the uncertainty of AES intensity measurements that are addressed in this International Standard: (i) the repeatability of intensity measurements and (ii) the drift of the intensities with time. Repeatability is important for analysing the trends and
25、 differences between samples that are similar. The instrumental issues that limit the measurement repeatability include the stability of the electron beam source, the settings of the detector, the sensitivity of the instrument to the sample placement, the data acquisition parameters and the data-pro
26、cessing procedure. The drift of the instrument intensity scale will limit the overall accuracy of any quantitative interpretation and arises from such effects as the ageing of components of the structure of the spectrometer, of its electronic supplies and of the detector. In AES instruments, it has
27、been found that, in service, the instrument intensity/energy response function may change as the instrument ages. This International Standard describes a simple method for determining the repeatability and constancy of the intensity scale of the instrument so that remedial action, such as improving
28、the operating procedure, resetting of the instrument parameters or recalibration of the intensity/energy response function, may be made. This method should, therefore, be conducted at regular intervals and is most useful if the data include a period in which the instrument has been checked to be wor
29、king correctly by the manufacturer or other appropriate body. This method uses a sample of pure copper (Cu) and is applicable to Auger electron spectrometers with an electron gun with a beam energy of 2 keV or greater. This method does not address all of the possible defects of instruments since the
30、 required tests would be very time-consuming and need both specialist knowledge and equipment. This method is, however, designed to address the basic common problem of repeatability and of drift of the intensity scales of AES instruments. This method may be conducted at the same time as the spectrom
31、eter energy calibration using ISO 179731or ISO 179742 . BSISO24236:2005blank 5002:63242OSISBINTENRATIONAL TSANDADR IS:63242 O5002(E)I SO 5002 All irthgs ersedevr 1Surface chemical analysis Auger electron spectroscopy Repeatability and constancy of intensity scale 1 Scope This International Standard
32、specifies a method for evaluating the constancy and repeatability of the intensity scale of Auger electron spectrometers, for general analytical purposes, using an electron gun with a beam energy of 2 keV or greater. It is only applicable to instruments that incorporate an ion gun for sputter cleani
33、ng. It is not intended to be a calibration of the intensity/energy response function. That calibration may be made by the instrument manufacturer or other organization. The present procedure provides data to evaluate and confirm the accuracy with which the intensity/energy response function remains
34、constant with instrument usage. Guidance is given on some of the instrumental settings that may affect this constancy. 2 Symbols H Laverage peak-to-peak height of the Cu L 3 VV peak in the differential mode H Lja value contributing to H Lfor the jth measurement in a set of measurements H Maverage pe
35、ak-to-peak height of the Cu M 2,3 VV peak in the differential mode H Mja value contributing to H Mfor the jth measurement in a set of measurements i identifier for one of the five parameters P ij index for one of the individual measurements of the parameter P ijN Laverage maximum intensity at the Cu
36、 L 3 VV peak in the direct mode N Lja value contributing to N Lfor the jth measurement in a set of measurements N Maverage maximum intensity at the Cu M 2,3 VV peak in the direct mode N Mja value contributing to N Mfor the jth measurement in a set of measurements P iparameter representing the mean v
37、alue of any of H L , H M , N L , N Mand H L /H MP ijthe jth measurement of a parameter with average value P iU 95 (P i ) uncertainty in the mean value of P i , at 95 % confidence level W peak full width at half maximum height analogue system scan rate value of the tolerance limit for H L /H Mfor com
38、pliance at 95 % confidence level (set by the analyst) (P i ) repeatability standard deviation for the parameter P i analogue detection system time constant BSISO24236:2005IS:63242 O5002(E) 2 I SO 5002 All irthgs ersedevr3 Outline of method Here, the method is outlined so that the detailed procedure,
39、 given in Clause 4, may be understood in context. To evaluate an Auger electron spectrometer using this procedure, it is necessary to obtain and prepare a copper reference foil in order to measure the intensities of the Cu M 2,3 VV and Cu L 3 VV Auger electron peaks with the appropriate instrumental
40、 settings. These peaks are chosen as they are near the middle and low kinetic-energy limits used in practical analysis. These peaks are well established for this purpose and relevant reference data exist. The low-energy, Cu M 2,3 VV, peak is chosen to be in an energy range where stray magnetic field
41、s can cause unwanted intensity changes and hence serves to monitor this problem. The initial steps of procuring the sample and setting up the instrument are described from 4.1 to 4.5, as shown in the flowchart of Figure 1, with the relevant subclause headings paraphrased. From 4.6, a user will move
42、to 4.7 unless there has been a previous determination of the intensity repeatability. In 4.7, measurements are made of the intensities of the Cu M 2,3 VV and Cu L 3 VV peaks in a sequence repeated seven times. These data give the repeatability standard deviations of the peak intensities. These repea
43、tabilities have contributions from the stability of the electron beam intensity, the spectrometer detector and the electronic supplies, from the sensitivity of the measured peak intensity to the sample position and from the statistical noise at the peak. In the method, conditions are defined to ensu
44、re that the statistical noise at the measured intensities is relatively small. This is discussed in Annex A. The value of the repeatability standard deviation may depend on the sample-positioning procedure. In 4.7.1, the use of a consistent sample-positioning procedure is required and the final cali
45、bration is only valid for samples positioned using this positioning procedure. The absolute values of the intensities of the two peaks are known for well-defined conditions and so, in principle, these two intensity values could be used to establish part of the spectrometer intensity/energy response
46、function3 . However, these response functions may have a complex dependence on energy4and so a determination of the intensities at two energies is insufficient. In this method, therefore, the scope is limited to evaluating the constancy of the intensity/energy response function as indicated by the c
47、onstancy of the intensities at these two energies and of the ratio of their intensities, within an uncertainty derived from the measurement repeatability. These determinations are made in 4.7 and the calculation is based on these measurements and performed in 4.8, as shown in the flowchart of Figure
48、 1. Following this, the first of the simpler regular determinations of intensity constancy is made in 4.9. In practice, the intensity/energy response function of spectrometers may change significantly with instrument use. If this occurs, it may modify quantified results deduced from spectra. In this
49、 case, it is important to consider the following actions: (i) improving the sample positioning, (ii) using longer warm-up times, (iii) re-setting the equipment to regain the original response function, (iv) re-determining the relative sensitivity factors used for quantification either experimentally or by calculation, or (v) increasing the stated uncertainty of any quantified results obtained. The choice of action will depend on the requi
