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ASTM E995-04

(Guide)

Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy

Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy

SIGNIFICANCE AND USE
Background subtraction techniques in AES were originally employed as a method of enhancement of the relatively weak Auger signals to distinguish them from the slowly varying background of secondary and backscattered electrons. Interest in obtaining useful information from the Auger peak line shape, concern for greater quantitative accuracy from Auger spectra, and improvements in data gathering techniques, have led to the development of various background subtraction techniques.
Similarly, the use of background subtraction techniques in XPS has evolved mainly from the interest in the determination of chemical states (binding energy values), greater quantitative accuracy from the XPS spectra, and improvements in data acquisition. Post-acquisition background subtraction is normally applied to XPS data.
The procedures outlined are popular in XPS and AES. General reviews of background subtraction techniques have been published (1 and 2 ).3
SCOPE
1.1 The purpose of this guide is to familiarize the analyst with the principal background subtraction techniques presently in use together with the nature of their application to data acquisition and manipulation.
1.2 This guide is intended to apply to background subtraction in electron, X-ray, and ion-excited Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS).
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

Status
Historical
Publication Date
30-Jun-2004
ICS
17.180.30 - Optical measuring instruments
Technical Committee
E42 - Surface Analysis
Drafting Committee
E42.03 - Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy
Current Stage
Ref Project

Relations

Replaces
ASTM E995-97 - Standard Guide for Background Subtraction Techniques in Auger Electron and X-ray Photoelectron Spectroscopy
Effective Date
01-Jul-2004
Replaced By
ASTM E995-11 - Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy
Effective Date
15-Oct-2011
Referred By
ASTM E2735-14(2020) - Standard Guide for Selection of Calibrations Needed for X-ray Photoelectron Spectroscopy (XPS) Experiments
Effective Date
01-Jul-2004
Referred By
ASTM E996-19 - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
Effective Date
01-Jul-2004

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ASTM E995-04 - Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-ray Photoelectron SpectroscopyASTM E995-04 - Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
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ASTM E995-04 - Standard Guide for Background Subtraction Techniques in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E995–04
Standard Guide for
Background Subtraction Techniques in Auger Electron
1
Spectroscopy and X-ray Photoelectron Spectroscopy
This standard is issued under the fixed designation E995; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope maximum for elastically backscattered electrons at the energy
of the incident electron beam. An additional source of back-
1.1 The purpose of this guide is to familiarize the analyst
ground is associated with Auger electrons, which are inelasti-
with the principal background subtraction techniques presently
cally scattered while traveling through the specimen. Auger
in use together with the nature of their application to data
electron excitation may also occur by X-ray and ion bombard-
acquisition and manipulation.
ment of surfaces.
1.2 This guide is intended to apply to background subtrac-
4.1.2 XPS—The production of electrons from X-ray excita-
tion in electron, X-ray, and ion-excited Auger electron spec-
tion of surfaces may be grouped into two categories—
troscopy (AES), and X-ray photoelectron spectroscopy (XPS).
photoemission of electrons and the production of Auger
1.3 This standard does not purport to address all of the
electrons from the decay of the resultant core hole states. The
safety concerns, if any, associated with its use. It is the
source of the background signal observed in the XPS spectrum
responsibility of the user of this standard to establish appro-
includes a contribution from inelastic scattering processes, and
priate safety and health practices and determine the applica-
for non-monochromatic X-ray sources, electrons produced by
bility of regulatory limitations prior to use.
Bremsstrahlung radiation.
2. Referenced Documents
4.2 Various background subtraction techniques have been
2
employed to diminish or remove the influence of these back-
2.1 ASTM Standards:
ground electrons from the shape and intensity of Auger
E673 Terminology Relating to Surface Analysis
electron and photoelectron features. Relevance to a particular
E996 Practice for Reporting Data in Auger Electron Spec-
analytical technique (AES or XPS) will be indicated in the title
troscopy and X-ray Photoelectron Spectroscopy
of the procedure.
3. Terminology
4.3 Implementation of any of the various background tech-
niquesthataredescribedinthisguidemaydependonavailable
3.1 Definitions—For definitions of terms used in this guide,
instrumentation and software as well as the method of acqui-
refer to Terminology E673.
sitionoftheoriginalsignal.Thesesubtractionmethodsfallinto
4. Summary of Guide
two general categories: (1) real-time background subtraction;
and (2) post-acquisition background subtraction.
4.1 Relevance to AES and XPS:
4.1.1 AES—TheproductionofAugerelectronsbybombard-
5. Significance and Use
ment of surfaces with electron beams is also accompanied by
5.1 Background subtraction techniques in AES were origi-
emission of secondary and backscattered electrons. These
nally employed as a method of enhancement of the relatively
secondary and backscattered electrons create a background
weak Auger signals to distinguish them from the slowly
signal.This background signal covers the energy spectrum and
varying background of secondary and backscattered electrons.
hasamaximum(near10eVfortruesecondaries),andasecond
Interest in obtaining useful information from the Auger peak
line shape, concern for greater quantitative accuracy from
1
This guide is under the jurisdiction of ASTM Committee E42 on Surface
Auger spectra, and improvements in data gathering techniques,
Analysis and is the direct responsibility of Subcommittee E42.03 onAuger Electron
have led to the development of various background subtraction
Spectroscopy and XPS.
Current edition approved July 1, 2004. Published August 2004. Originally techniques.
approved in 1984. Last previous edition approved in 1997 as E995 – 97. DOI:
5.2 Similarly, the use of background subtraction techniques
10.1520/E0995-04.
in XPS has evolved mainly from the interest in the determina-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tion of chemical states (binding energy values), greater quan-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on titative accuracy from the XPS spectra, and improvements in
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

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E995–04
dat
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6.2  
Illumination of Photocathode  
6.3  
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6.4  
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SIGNIFICANCE AND USE
4.1 This practice describes the essential components of a wavelength dispersive X-ray spectrometer. This description is presented so that the user may gain a general understanding of the structure of an X-ray spectrometer system. It also provides a means for comparing and evaluating different systems as well as understanding the capabilities and limitations of each instrument.  
4.2 A laboratory may implement this practice or an X-ray fluorescence method in partnership with a manufacturer of the analytical instrumentation. If a laboratory chooses to consult with an instrument manufacturer, then the following should be considered. The laboratory should know the alloy matrices to be analyzed, elements and mass fraction ranges to be determined, and the expected performance requirements for each of these elements. The laboratory should inform the instrument manufacturer of these requirements so an analytical method may be developed which meets the laboratory’s expectations. Typically, instrument manufacturers customize the instrument configuration to satisfy the end-user’s requirements for elemental coverage, elemental precision, and detection limits. Instrument manufacturer developed analytical methods may include specific parameters for sample excitation, wavelengths, inter-element interference corrections, calibration and regression, equipment configuration/installation, and sample preparation requirements. Laboratories should have a basic understanding of the parameters derived by the manufacturer.
SCOPE
1.1 This practice covers the components of a wavelength dispersive X-ray spectrometer that are basic to its operation and to the quality of its performance. It is not the intent of this practice to specify component tolerances or performance criteria, as these are unique for each instrument. However, the practice does attempt to identify which tolerances are critical and thus which should be specified.  
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific safety hazard statements are given in Section 7.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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  • Standard
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    English language
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