BS ISO 17974-2002 Surface chemical analysis - High-resolution Auger electron spectrometers - Calibration of energy scales for elemental and chemical-state analysis《表面化学分析 高分辨率螺旋电子光.pdf

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1、BRITISH STANDARD BS ISO 17974:2002 Surface chemical analysis High-resolution Auger electron spectrometers Calibration of energy scales for elemental and chemical-state analysis ICS 71.040.40 BS ISO 17974:2002 This British Standard, having been prepared under the direction of the Materials and Chemic

2、als Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 29 November 2002 BSI 29 November 2002 ISBN 0 580 40848 5 National foreword This British Standard reproduces verbatim ISO 17974:2002 and implements it as the UK national stand

3、ard. The UK participation in its preparation was entrusted to Technical Committee CII/60, Surface chemical analysis, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implem

4、ent international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport

5、 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 confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee a

6、ny enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate 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 b

7、lank page, pages 1 to 27 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 17974:2002(E)INTERNATIONAL STANDARD ISO 17974 First edition 2002-10-01 Surface che

8、mical analysis High- resolution Auger electron spectrometers Calibration of energy scales for elemental and chemical-state analysis Analyse chimique des surfaces Spectromtres dlectrons Auger haute rsolution talonnage des chelles dnergie pour lanalyse lmentaire et de ltat chimique BSISO17974:2002BSIS

9、O17974:2002iiIS:47971 O2002(E) I SO 2002 All irthgs ersedevr iiiContents Page Foreword iv Introduction. v 1 Scope 1 2 Normative reference 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms 2 5 Outline of method 3 6 Procedure for calibrating the energy scale 6 6.1 Obtaining reference sample

10、s. 6 6.2 Mounting samples. 6 6.3 Cleaning samples 6 6.4 Choosing spectrometer settings for energy calibration.6 6.5 Operating the instrument . 7 6.6 Options for initial or subsequent calibration measurements. 7 6.7 Measurements for peak kinetic energy repeatability standard deviation and scale linea

11、rity. 8 6.8 Calculating peak kinetic energy repeatability standard deviation. 10 6.9 Determining relevant reference kinetic energies. 12 6.10 Checking kinetic energy scale linearity 13 6.11 Procedure for regular calibration error determination 14 6.12 Procedures for correction of the instrument kine

12、tic energy scale 15 6.13 Next calibration . 17 6.14 Establishing calibration intervals 17 Annex A (normative) Maximum number of points for a single application of Savitzky and Golay smoothing of peaks at 0,1 eV energy intervals 19 Annex B (normative) Least squares determination of peak kinetic energ

13、y by a simple computational method 20 Annex C (informative) Derivation of uncertainties 23 Annex D (informative) Citation of uncertainties of measured kinetic energies . 25 Bibliography 27 BSISO17974:2002iiiIS:47971 O2002(E) vi I SO 2002 All irthgs ersedevrForeword ISO (the International Organizatio

14、n 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

15、 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. Inter

16、national Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publicat

17、ion 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 of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all su

18、ch patent rights. ISO 17974 was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee SC 7, X-ray photoelectron spectroscopy. BSISO17974:2002ivIS:47971 O2002(E) I SO 2002 All irthgs ersedevr vIntroduction Auger electron spectroscopy (AES) is used extensively for the sur

19、face analysis of materials. Elements in the sample (with the exception of hydrogen and helium) are identified from comparisons of the kinetic energies of their Auger electron peaks (determined from the measured spectra) with tabulations of those energies for the different elements or with handbooks

20、of spectra. Information on the chemical state of such elements can be derived from the chemical shifts of measured Auger electron features with respect to those for reference states. Identification of chemical states is based on measurements of chemical shifts with accuracies in the range down to 0,

21、1 eV, making necessary individual measurements having and reference sources available with, the appropriate accuracies. Calibrations of the kinetic energy scales of AES instruments are therefore required, often with an uncertainty of u 0,3 eV. The method for calibrating kinetic energy scales specifi

22、ed in this International Standard uses metallic samples of pure copper (Cu), and either aluminium (Al) or gold (Au), and is applicable to Auger electron spectrometers measuring direct spectra with relative resolutions of 0,2 % or better. It is valid for the kinetic energy range 0 eV to 2 250 eV if g

23、old is used, and 0 eV to 1 550 eV if aluminium is used. Traditionally, kinetic energies of Auger electrons have been referenced to the 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

24、0,5 eV. Although use of the vacuum level reference procedure will generally not cause ambiguity in elemental identification, it may cause uncertainty in measurements at high resolution relating to chemical states. Because of this, instruments designed for both Auger electron spectroscopy and X-ray p

25、hotoelectron spectroscopy reference the kinetic energies to the Fermi level, giving values typically 4,5 eV higher than those referenced to the vacuum level. For the purposes of this International Standard, the kinetic energies are referenced to the Fermi level. AES instruments calibrated for provid

26、ing analyses within the scope of ISO 17025 1as well as for other purposes may need a statement of the estimated calibration uncertainty. These instruments are in calibration for kinetic energy measurements within certain defined tolerance limits . The value of is not defined in this International St

27、andard since it will depend on the application and design of the AES instrument. The value of is selected by the user, based on experience in the use of this International Standard, the calibration stability of the instrument, the uncertainty required for kinetic energy measurements in the intended

28、applications of the instrument and the effort incurred in conducting the calibration. This International Standard provides information by which a suitable value of may be chosen. Typically, is W 0,2 eV and greater than about four times the repeatability standard deviation, R . For an instrument to b

29、e in calibration, the divergence from the reference kinetic energy values plus the expanded calibration uncertainty for a confidence level of 95 %, when added to the instrumental drift with time, must not exceed the chosen tolerance limits. Before it becomes likely that the instrument is out of cali

30、bration, it needs to be recalibrated: a calibration measurement made and action taken to reduce the difference between the measured and reference values. This difference may not necessarily be reduced to zero, but will normally come down to a small fraction of the tolerance limits required for the a

31、nalytical work. This International Standard does not address all possible defects of instruments, since the required tests would be very time consuming and would need both specialist knowledge and equipment. However, it does address the basic and common problems in the calibration of the kinetic ene

32、rgy scales of AES instruments. BSISO17974:2002vINTENRATIONAL TSANDADR IS:47971 O2002(E)I SO 2002 All irthgs ersedevr 1Surface chemical analysis High-resolution Auger electron spectrometers Calibration of energy scales for elemental and chemical-state analysis 1 Scope This International Standard spec

33、ifies a method for calibrating the kinetic energy scales of Auger electron spectrometers used for elemental and chemical state analysis at surfaces. It also specifies a calibration schedule for testing the kinetic energy scale linearity at one intermediate energy, for confirming the uncertainty of t

34、he scale calibration at one low and one high kinetic energy value, for correcting for small drifts of that scale and for defining the expanded uncertainty of the calibration of the kinetic energy scale with a confidence level of 95 % (this uncertainty includes contributions for behaviours observed i

35、n interlaboratory studies but does not cover all possible defects). It is applicable only to those instruments incorporating an ion gun for sputter cleaning. It is not applicable to instruments with kinetic energy scale errors significantly non-linear with energy. Neither it is applicable to those i

36、nstruments operated at relative resolutions poorer than 0,2 % in the constant E/E mode or 1,5 eV in the constant E mode, those requiring tolerance limits of 0,05 eV or less, nor to those with an electron gun that cannot be operated in the energy range 5 keV to 10 keV. It does not provide a full cali

37、bration check for confirming the energy measured at each addressable point on the energy scale, this being performed according to the manufacturers recommendations. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions

38、 of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the norma

39、tive document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 18115, Surface chemical analysis Vocabulary 3 Terms and definitions For the purposes of t

40、his International Standard, the terms and definitions given in ISO 18115 apply. BSISO17974:20021IS:47971 O2002(E) 2 I SO 2002 All irthgs ersedevr4 Symbols and abbreviated terms The following symbols and abbreviated terms are used throughout this International Standard (see also annex B) AES Auger el

41、ectron spectroscopy A Analyser retardation factor a Measured energy scaling error b Measured zero offset error, in electronvolts c Coefficient of R d Coefficient of R 2E corrCorrected result for kinetic energy corresponding to given E meas , in electronvolts E elemKinetic energy of a frequently meas

42、ured element at which the indicated kinetic energy scale is set, after calibration, to read correctly, in electronvolts E measA measured kinetic energy, in electronvolts E meas,n Average measured kinetic energy for peak n, in electronvolts E meas,ni One of a set of measurements of kinetic energy for

43、 peak n, in electronvolts E ref,n Reference values for position of peak n on kinetic energy scale, in electronvolts o ref,n E Reference kinetic energy of peak n FWHM Full width at half maximum peak intensity above background, in electronvolts i Index of spectrum for the seven repeat measurements of

44、a peak j Number of repeat measurements for new peak k Number of repeat measurements for Cu M 2,3 VV, Cu L 3 VV, and Au M 5 M 6,7 N 6,7or Al KL 2,3 L 2,3peaks in repeatability and linearity determinations m Number of repeat measurements for Cu M 2,3 VV and Au M 5 N 6,7 N 6,7or Al KL 2,3 L 2,3peaks in

45、 regular calibrations n Designation of peak identifier R Relative resolution of a spectrometer, expressed as percentage t xStudents t values for x degrees of freedom of two-sided distribution for confidence level of 95 % U 95Total uncertainty of calibrated energy scale at confidence level of 95 %, i

46、n electronvolts c 95 U (E) Uncertainty at confidence level of 95 % arising from calibration using Cu M 2,3 VV and Au M 5 N 6,7 N 6,7or Al KL 2,3 L 2,3peaks at kinetic energy, E, assuming perfect scale linearity, in electronvolts l 95 U Uncertainty of 2at confidence level of 95 %, in electronvolts cl

47、 95 U Uncertainty of calibration at confidence level of 95 %, in the absence of a linearity error n Offset energy, given by average measured kinetic energy for calibration peak minus reference kinetic energy, in electronvolts, for n = 1, 2, 3, 4 E corrCorrection added to E measafter calibration to p

48、rovide corrected kinetic energy result Average of 1and 4BSISO17974:20022IS:47971 O2002(E) I SO 2002 All irthgs ersedevr 3 Value for tolerance limit of energy calibration at confidence level of 95 % (set by the analyst), in electronvolts 2Measured scale linearity error at Cu L 3 VV peak, in electronv

49、olts RMaximum of R1 , R2 , and R3or R4 RnRepeatability standard deviation for nth peak RnewRepeatability standard deviation for new peak, in electronvolts See annex B for a list of symbols used only in that annex. 5 Outline of method Calibration of an Auger electron spectrometer using this International Standard is performed by obtaining and preparing copper and gold or aluminium reference foils in order