1、BS ISO29081:2010ICS 71.040.40NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDSurface chemicalanalysis Augerelectron spectroscopy Reporting ofmethods used forcharge control andcharge correctionThis British Standardwas published under theauthority of the Standards
2、Policy and StrategyCommittee on 28 February2010 BSI 2010ISBN 978 0 580 63478 9Amendments/corrigenda issued since publicationDate CommentsBS ISO 29081:2010National forewordThis British Standard is the UK implementation of ISO 29081:2010.The UK participation in its preparation was entrusted to Technic
3、alCommittee CII/60, Surface chemical analysis.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a B
4、ritish Standard cannot confer immunityfrom legal obligations.BS ISO 29081:2010Reference numberISO 29081:2010(E)ISO 2010INTERNATIONAL STANDARD ISO29081First edition2010-02-15Surface chemical analysis Auger electron spectroscopy Reporting of methods used for charge control and charge correction Analys
5、e chimique des surfaces Spectroscopie des lectrons Auger Indication des mthodes mises en uvre pour le contrle et la correction de la charge BS ISO 29081:2010ISO 29081:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be pri
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10、1 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2010 All rights reservedBS ISO 29081:2010ISO 29081:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Symbols
11、 and abbreviated terms 1 5 Apparatus.2 5.1 Charge-control technique.2 5.2 Special apparatus2 5.3 Specimen mounting and preparation3 5.4 Instrument calibration.3 6 Reporting of information related to charge control.3 6.1 Methods of charge control .3 6.2 Reasons for needing charge control and choice o
12、f method 3 6.3 Specimen information.3 6.3.1 Specimen form.3 6.3.2 Specimen dimensions.4 6.3.3 Specimen-mounting methods4 6.3.4 Specimen treatment prior to or during analysis 4 6.4 Values of experimental parameters.4 6.5 Information on the effectiveness of methods of charge control4 7 Reporting of me
13、thod(s) used for charge correction and the value of that correction.5 7.1 Methods of charge correction5 7.2 Approach5 7.3 Value of correction energy .5 Annex A (informative) Description of methods of charge control for Auger electron spectroscopy6 A.1 Introduction6 A.2 Hierarchical table of methods
14、for reducing charging7 A.3 Methods for minimizing charging during AES .9 A.3.1 Introduction9 A.3.2 Decreasing specimen resistivity9 A.3.3 Decreasing the insulator thickness (or effective insulator thickness) 9 A.3.4 Reducing the current density, limiting primary-electron dose and using additional cu
15、rrent sources.11 A.3.5 Optimizing the total secondary-electron emission yield.12 A.4 Considerations for highly non-uniform specimens, fibres and particles and the use of sputter depth profiling 14 A.4.1 Introduction14 A.4.2 Dealing with rough surfaces, particles, fibres and other non-uniform specime
16、ns14 A.4.3 Sputter depth profiling14 A.5 General considerations concerning charge build-up during AES .15 A.5.1 Introduction15 A.5.2 Resistivity, capacitance and surface potential 15 A.5.3 Total secondary-electron yield and surface potential .17 A.5.4 Charge transport and accumulation below the surf
17、ace, time-dependent charge accumulation and specimen damage20 Bibliography21 BS ISO 29081:2010ISO 29081:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of pre
18、paring 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
19、 liaison with ISO, also take part in the 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
20、 of technical committees is to prepare 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
21、 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. ISO 29081 was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee SC 5, Auger
22、electron spectroscopy. BS ISO 29081:2010ISO 29081:2010(E) ISO 2010 All rights reserved vIntroduction Auger electron spectroscopy (AES) is widely used for characterization of surfaces of materials. Elements in the sample (with the exception of hydrogen and helium) are identified from comparisons of A
23、uger transition energies, determined from measured Auger spectra, with tabulations of these energies for the various elements. Although Auger electrons are observed during X-ray irradiation of specimens (X-ray photoelectron spectroscopy), AES, as used in this document, is associated with electron ir
24、radiation of a specimen. Because the incident electron beam can be focused to sizes approximating 10 nm, AES is an important tool for characterization of small surface features and of nanostructured materials. Information on the elements present, and sometimes the chemical state of the detected elem
25、ents, can frequently be obtained from examination of the line shape and energies of the peaks (see ISO/TR 1839443). Reliable determination of elements present requires appropriate calibration of the energy scale (as described in ISO 17973 and ISO 17974). The surface potential of an insulating specim
26、en may change during an AES measurement due to the build-up of surface and near-surface electrical charge, and this charge can shift the energy of Auger electrons, thus complicating elemental (and chemical state) identification, especially when a negative surface potential moves the Auger spectrum a
27、bove the energy interval selected by the electron analyser. The build-up of surface potential can also move the location of the electron beam, effectively shifting the region on the specimen or even off the specimen that is being analysed. Similar changes occur for metals during electron irradiation
28、 if they are not connected to ground. This would occur, for example, if small metal particles are incorporated in an insulating matrix. Depending on the secondary-electron yield, the surface potential may shift positively or negatively. In some circumstances, these two shifts (energy and position) c
29、reate an unstable feedback system, rendering the collection of AES spectra nearly impossible. In addition to changes in the Auger-electron peak energy and intensity, the specimen surface composition might be altered (specimen damage) directly by the incident electron beam or due to electric-field-in
30、duced diffusion when a field is set up in the surface region of the specimen. A variety of methods and approaches have been developed to control and minimize charging effects in AES. The application of a particular method can be highly dependent on the details of the instrument being used, the size
31、and shape of the specimen being examined, the specimen morphology and composition, and the information to be collected. Although the build-up of surface charge can complicate analysis, in some circumstances it can also be used creatively as a tool to gain information about the specimen. The amount o
32、f induced charge near the surface, its distribution across the specimen surface, and its dependence on experimental conditions are determined by many factors, including those associated with the specimen and the characteristics of the spectrometer. Charge build-up is a well-studied1three-dimensional
33、 phenomenon that occurs along the specimen surface and into the material. Charge build-up may also occur at phase boundaries or interface regions within the depth of a specimen that is irradiated by electrons. Some specimens undergo time-dependent changes in charge build-up due to charge trapping, c
34、hemical changes or component diffusion or volatilization induced by heating or by incident or secondary electrons. Such specimens may never achieve steady-state potentials. There is, at present, no universally applicable method or set of methods for charge control or for charge correction in AES2,3.
35、 This International Standard specifies the information that has to be provided to document the method of charge control during data acquisition and/or the method of charge correction during data analysis of insulating specimens. Information is given in Annex A on common methods for charge control th
36、at can be useful for many applications. The particular charge-control method that may be chosen in practice depends on the type of specimen (e.g. powder, thin film or thick specimen), the nature of the instrumentation, the size of the specimen and the extent to which the specimen surface might be mo
37、dified by a particular procedure. To assist an analyst, a summary table lists the common charge-control methods in approximate order of simplicity of application. This International Standard has two main areas of application. First, it identifies information on methods of charge control and/or charg
38、e correction to be included in reports of AES measurements (e.g. from an analyst to a customer or in publications) in order to evaluate and reproduce data on insulating materials and to ensure that measurements on similar materials can be meaningfully compared. Second, adherence to the International
39、 Standard will enable published AES spectra to be used with confidence by other analysts. BS ISO 29081:2010BS ISO 29081:2010INTERNATIONAL STANDARD ISO 29081:2010(E) ISO 2010 All rights reserved 1Surface chemical analysis Auger electron spectroscopy Reporting of methods used for charge control and ch
40、arge correction 1 Scope This International Standard specifies the minimum amount of information required for describing the methods of charge control in measurements of Auger electron transitions from insulating specimens by electron-stimulated Auger electron spectroscopy and to be reported with the
41、 analytical results. Information is provided in Annex A on methods that have been found useful for charge control prior to or during AES analysis. This annex also contains a table summarizing the methods or approaches, ordered by simplicity of approach. Some methods will be applicable to most instru
42、ments, others require special hardware, others might involve remounting the specimen or changing it. A similar International Standard has been published for X-ray photoelectron spectroscopy (ISO 1931844). 2 Normative references The following referenced documents are indispensable for the application
43、 of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 17973, Surface chemical analysis Medium-resolution Auger electron spectrometers Calibration of energy scales for elem
44、ental analysis ISO 17974, Surface chemical analysis High-resolution Auger electron spectrometers Calibration of energy scales for elemental and chemical-state analysis ISO 18115, Surface chemical analysis Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions
45、 given in ISO 18115 apply. 4 Symbols and abbreviated terms AES Auger electron spectroscopy Epprimary-electron energy, in keV Ep(max)energy at which the TSEEY is a maximum E0p1energy at which the secondary-electron emission yield rises above unity E0p2energy at which the secondary-electron emission y
46、ield drops below unity BS ISO 29081:2010ISO 29081:2010(E) 2 ISO 2010 All rights reservedEcp2energy at which the range of the incident electrons is approximately equal to the maximum escape depth of the secondary electrons FIB focused ion beam FWHM full width at half maximum, in eV Ipprimary-electron
47、 current Issecondary-electron current jpcurrent density of the primary-electron beam on the specimen surface KEcorrcorrected kinetic energy, in eV KEmeasmeasured kinetic energy, in eV KErefreference kinetic energy, in eV N charging index R range of primary electrons SEM scanning electron microscopy
48、t electron irradiation time TSEEY total secondary-electron emission yield Ussurface potential Veelectron interaction volume z specimen thickness electrical resistivity of the specimen total secondary-electron yield angle of incidence of primary-electron beam on the specimen with respect to the surfa
49、ce normal, in degrees corrcorrection energy, to be added to measured Auger electron energies for charge correction, in eV 5 Apparatus 5.1 Charge-control technique One or more of the charge-control techniques described in Clause A.3 may be employed in most AES spectrometers. The AES instrument shall be operated in accordance with the manufacturers or other documented procedures. 5.2 Special apparatus Some of the techniques outlined in Clause A.3 require special apparatus, such as a low-energy ion source or a source
