ASTM E827-95
(Practice)Standard Practice for Indentifying Elements by the Peaks in Auger Electron Spectroscopy
Standard Practice for Indentifying Elements by the Peaks in Auger Electron Spectroscopy
SCOPE
1.1 This practice outlines the necessary steps for the identification of elements in a given Auger spectrum obtained using conventional electron spectrometers. Spectra displayed as either the electron energy distribution (direct spectrum) or the first derivative of the electron energy distribution are considered.
1.2 This practice applies to Auger spectra generated by electron or X-ray bombardment of the specimen surface and can be extended to spectra generated by other methods such as ion bombardment.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 827 – 95
Standard Practice for
Elemental Identification by Auger Electron Spectroscopy
This standard is issued under the fixed designation E 827; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope reference spectra from pure element or stoichiometric com-
pound standards, or both, with which an unknown spectrum
1.1 This practice outlines the necessary steps for the iden-
can be compared.
tification of elements in a given Auger spectrum obtained using
4.3 An element in an Auger spectrum is considered posi-
conventional electron spectrometers. Spectra displayed as ei-
tively identified if the peak shapes, the peak energies, and the
ther the electron energy distribution (direct spectrum) or the
relative signal strengths of peaks from the unknown coincide
first derivative of the electron energy distribution are consid-
with those from a standard reference spectrum of the element
ered.
or compound.
1.2 This practice applies to Auger spectra generated by
electron or X-ray bombardment of the specimen surface; it
5. Significance and Use
does not apply to Auger spectra generated by other methods
5.1 Auger analysis is used to determine the elemental
such as ion bombardment.
composition of the first few atomic layers, typically 0.5 to
1.3 This standard does not purport to address all of the
2.0-nm thick, of a specimen surface. In conjunction with inert
safety concerns, if any, associated with its use. It is the
gas ion sputtering, it is used to determine the sputter depth
responsibility of the user of this standard to establish appro-
profile to a depth of a few micrometres.
priate safety and health practices and determine the applica-
5.2 The specimen is normally a solid conductor, semicon-
bility of regulatory limitations prior to use.
ductor, or insulator. For insulators, provisions may be required
2. Referenced Documents for control of charge accumulation at the surface (see Guide
E 1523). Typical applications include the analysis of thin film
2.1 ASTM Standards:
deposits or segregated overlayers on metallic or alloy sub-
E 673 Terminology Relating to Surface Analysis
strates. The specimen topography may vary from a smooth,
E 983 Guide for Minimizing Unwanted Electron Beam
2 polished specimen to a rough fracture surface.
Effects In Auger Electron Spectroscopy
5.3 Auger analysis of specimens with volatile species that
E 984 Guide for Identifying Chemical Effects and Matrix
2 evaporate in the ultra-high vacuum environment of the Auger
Effects in Auger Electron Spectroscopy
chamber and substances which are susceptible to electron or
E 1523 Guide to Charge Control and Charge Referencing
2 X-ray beam damage, such as organic compounds, may require
Techniques in X-Ray Photoelectron Spectroscopy
special techniques not covered herein. (See Guide E 983.)
3. Terminology
6. Apparatus
3.1 Terms used in Auger electron spectroscopy are defined
6.1 Electron Energy Analyzers, such as retarding field ana-
in Terminology E 673.
lyzer, cylindrical mirror analyzer (single or double pass), or
4. Summary of Practice
hemispherical analyzer.
6.2 Standard Equipment, typically including an electron gun
4.1 The Auger spectrum is obtained with appropriate instru-
or X-ray source for excitation, an electron multiplier for
mental parameters from a low kinetic energy limit of approxi-
amplification of the Auger electron signal, and recording
mately 30 eV to an upper kinetic energy limit of approximately
instrumentation.
2000 eV or higher to include all the principal Auger electron
6.2.1 A vacuum capability in the test chamber is required to
energies of all elements (except H and He which do not have
allow analysis without contamination from the ambient atmo-
Auger transitions).
sphere; depending on specimen surface conditions, analysis is
4.2 This practice assumes the existence of appropriate
−3 −8
performed in the pressure range from 10 to 10 Pa.
7. Procedure
This practice is under the jurisdiction of ASTM Committee E-42 on Surface
Analysis and is the direct responsibility of Subcommittee E42.03 on Auger Electron
7.1 Identify the peak having the largest signal strength in the
Spectroscopy and XPS.
spectrum and note its peak energy and characteristic shape.
Current edition approved Sept. 10, 1995. Published November 1995. Originally
published as E 827 – 81. Last previous edition E 827 – 93.
Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 827
Note that peaks in direct and derivative spectra have different matrix effects (see Guide E 984). In this case, the reference
energies. spectrum should be that of the particular compound containing
7.2 Consult a list of peak energies for standard elements and the element.
note the possible energy matches. The peak position can vary
9. Discussion
by up to 20 eV with slightly differing chemistries, so include
9.1 The state-of-the-art in Auger electron spectroscopy now
elements within a wide range of energies around the peak
allows routine qualitative analysis without too many interpre-
position noted in 7.1.
tational difficulties. It is assumed that the practitioner employs
7.3 Consult the standard elemental spectrum for one of the
common practice in generating an Auger spectrum in order to
elements identified by 7.2, and look for the presence of
use this procedure. Under normal circumstances, all elements
additional confirming lines in the specimen spectrum that
(except H and He) present on a specimen surface being
match the standard spectrum. Direct and derivative standard
analyzed can be detected with a sensitivity limit of 1 atomic %
spectra are available. Compare the shape of the peaks as well.
or better.
If a good match is found, label all lines from the standard
9.2 Electron Beam Excitation—Typical parameters used for
spectrum that are visible in the specimen spectrum. If a match
electron beam excitation are 2 to 20 keV beam energy and
is not found, eliminate that element from further consideration
−10 −6
10 to 10 A beam current. The beam energy and beam
and select another element from the list found in
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.