ASTM E983-19

Standard Guide for Minimizing Unwanted Electron Beam Effects in Auger Electron Spectroscopy

SIGNIFICANCE AND USE
4.1 When electron beam excitation is used in AES, the incident electron beam can interact with the specimen material causing physical and chemical changes. In general, these effects are a hindrance to AES analysis because they cause localized specimen modification (1-4).5  
4.2 With specimens that have poor electrical conductivity the electron beam can stimulate the development of localized charge on the specimen surface. This effect is a hindrance to AES analysis because the potentials associated with the charge can either adversely affect the integrity of Auger data or make Auger data collection difficult (5, 6).
SCOPE
1.1 This guide outlines the origins and manifestations of unwanted electron beam effects in Auger electron spectroscopy (AES).  
1.2 Some general guidelines are provided concerning the electron beam parameters which are most likely to produce these effects and suggestions are offered on how to minimize them.  
1.3 General classes of materials are identified which are most likely to exhibit unwanted electron beam effects. In addition, a tabulation of some specific materials which have been observed to undergo electron damage effects is provided.  
1.4 A simple method is outlined for establishing the existence and extent of these effects during routine AES analysis.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2019
• ICS: 17.180.30 - Optical measuring instruments
• Technical Committee: E42 - Surface Analysis
• Drafting Committee: E42.03 - Auger Electron Spectroscopy and X-Ray Photoelectron Spectroscopy

Relations

• Replaces: ASTM E983-10(2018) - Standard Guide for Minimizing Unwanted Electron Beam Effects in Auger Electron Spectroscopy
• Effective Date: 01-Apr-2019
• Refers: ASTM E996-10(2018) - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
• Effective Date: 01-Nov-2018
• Refers: ASTM E996-10 - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
• Effective Date: 01-Nov-2010
• Refers: ASTM E996-04 - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
• Effective Date: 01-Nov-2004
• Refers: ASTM E673-03 - Standard Terminology Relating to Surface Analysis (Withdrawn 2012)
• Effective Date: 01-Dec-2003
• Refers: ASTM E673-02a - Standard Terminology Relating to Surface Analysis
• Effective Date: 10-Dec-2002
• Refers: ASTM E673-01 - Standard Terminology Relating to Surface Analysis
• Effective Date: 10-Nov-2001
• Refers: ASTM E673-98E1 - Standard Terminology Relating to Surface Analysis
• Effective Date: 10-Nov-2001
• Refers: ASTM E996-94(1999) - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
• Effective Date: 10-Sep-1999
• Referred By: ASTM E1078-14(2020) - Standard Guide for Specimen Preparation and Mounting in Surface Analysis
• Effective Date: 01-Apr-2019
• Referred By: ASTM E984-12(2020) - Standard Guide for Identifying Chemical Effects and Matrix Effects in Auger Electron Spectroscopy
• Effective Date: 01-Apr-2019
• Referred By: ASTM E996-19 - Standard Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
• Effective Date: 01-Apr-2019

Overview

ASTM E983-19: Standard Guide for Minimizing Unwanted Electron Beam Effects in Auger Electron Spectroscopy (AES) provides comprehensive guidelines to recognize and mitigate unwanted electron beam-induced effects during AES analysis. Auger Electron Spectroscopy is a powerful technique for surface chemical analysis, but the electron beam used in this process can cause physical and chemical changes in samples, particularly in materials with poor electrical or thermal conductivity. These changes can degrade data quality, causing localized specimen modification, charging, or other undesirable alterations. The standard primarily supports laboratories and researchers aiming to improve Auger data integrity and reproducibility.

Key Topics

• Origins of Electron Beam Effects:
  The guide details how electron beam interaction can induce:

  • Charge accumulation, especially in insulators, causing Auger signal distortion.
  • Electronic excitation leading to dissociation, desorption, adsorption, polymerization, oxidation, reduction, decomposition, and other modifications.
  • Heating effects resulting in annealing, segregation, and chemical reactions.

• Material Susceptibility:
  Materials most prone to electron beam effects include:

  • Nonmetallic compounds (oxides, fluorides, chlorides, alkali halides, organics)
  • Adsorbed species (water, hydrocarbons, halogens)
  • Insulators and materials with poor electrical/thermal conductivity
  • Powders, fibers, or other configurations with limited specimen holder contact

• Electron Beam Parameters:
  The guide emphasizes the critical impact of:

  • Electron dose (total electrons per unit area)
  • Current density (current per unit area)
  • Beam energy, angle of incidence, and duration of exposure

• Observation and Minimization Methods:

  • Sequential spectral acquisition to detect ongoing changes
  • Adjusting electron beam current, energy, density, and incidence angle
  • Utilizing specimen cooling (e.g., liquid nitrogen)
  • Enhancing electrical/thermal contact via grounded foils, conductive masks, or grids

Applications

Implementing ASTM E983-19 is essential for:

• Materials Characterization:
  Ensures accurate Auger spectroscopy by minimizing artifacts from beam-induced changes, crucial in analyzing sensitive materials, thin films, insulators, or mobile ion-containing specimens.

• Research and Quality Assurance:
  Supports reliable data in surface science, microelectronics, catalysis, and coatings development, benefiting R&D labs in academic and industrial sectors.

• Instrument Calibration and Method Development:
  Provides practical procedures for establishing and reporting conditions that control electron beam effects, enabling reproducibility and comparability across studies.

• Training and Best Practices:
  Delivers a knowledge base for new AES users and advanced practitioners on mitigating unwanted beam-induced phenomena.

Related Standards

• ASTM E996:
  Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy - Helps standardize the documentation of AES parameters and outcomes.

• ISO 18115-1:2013:
  Surface Chemical Analysis - Vocabulary - Offers key terminology for AES and related techniques.

• Withdrawn ASTM E673:
  Provided earlier terminology relating to surface analysis.

Practical Value

By applying the guidelines of ASTM E983-19, laboratories can:

• Reduce electron beam-induced specimen modifications, preserving true surface chemistry.
• Detect and control unwanted phenomena such as charging, diffusion, and spectroscopy artifacts.
• Achieve more stable, reliable, and reproducible AES measurements across a wide range of materials.
• Enhance data quality for research, development, and quality control in materials science and surface engineering.

Keywords: Auger electron spectroscopy, electron beam effects, specimen charging, surface analysis, ASTM E983-19, electron beam damage, materials characterization, AES best practices

Standards Content (Sample)

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.
Designation: E983 − 19
Standard Guide for
Minimizing Unwanted Electron Beam Effects in Auger
Electron Spectroscopy
This standard is issued under the fixed designation E983; 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 E673 Terminology Relating to SurfaceAnalysis (Withdrawn
2012)
1.1 This guide outlines the origins and manifestations of
E996 Practice for Reporting Data in Auger Electron Spec-
unwanted electron beam effects inAuger electron spectroscopy
troscopy and X-ray Photoelectron Spectroscopy
(AES).
2.2 ISO Standard:
1.2 Some general guidelines are provided concerning the
ISO 18115-1:2013 Surface chemical analysis -- Vocabulary
electron beam parameters which are most likely to produce
-- Part 1: General terms and terms used in spectroscopy
these effects and suggestions are offered on how to minimize
3. Terminology
them.
3.1 See ISO 18115-1:2013 for terms used inAuger electron
1.3 General classes of materials are identified which are
spectroscopy.
most likely to exhibit unwanted electron beam effects. In
addition, a tabulation of some specific materials which have
NOTE 1—Electron beam effects and their consequences are widely
been observed to undergo electron damage effects is provided.
referred to in the literature using any one or more of the following terms:
electron beam damage, sample damage, specimen damage, beam effects,
1.4 A simple method is outlined for establishing the exis-
electron beam induced processes, and electron irradiation effects.
tence and extent of these effects during routine AES analysis.
4. Significance and Use
1.5 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this 4.1 When electron beam excitation is used in AES, the
standard. incident electron beam can interact with the specimen material
causing physical and chemical changes. In general, these
1.6 This standard does not purport to address all of the
effects are a hindrance to AES analysis because they cause
safety concerns, if any, associated with its use. It is the
localized specimen modification (1-4).
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4.2 With specimens that have poor electrical conductivity
mine the applicability of regulatory limitations prior to use.
the electron beam can stimulate the development of localized
1.7 This international standard was developed in accor-
charge on the specimen surface. This effect is a hindrance to
dance with internationally recognized principles on standard-
AES analysis because the potentials associated with the charge
ization established in the Decision on Principles for the
can either adversely affect the integrity of Auger data or make
Development of International Standards, Guides and Recom-
Auger data collection difficult (5, 6).
mendations issued by the World Trade Organization Technical
5. Origins of Electron Beam Effects
Barriers to Trade (TBT) Committee.
5.1 Electron beam effects inAES may originate from one or
2. Referenced Documents
more distinct processes.
5.1.1 Charge accumulation (7) (see Chapter 9) in materials
2.1 ASTM Standards:
with poor electrical conductivity leading to potentials that
cause distortion of Auger data or make AES data collection
This guide is under the jurisdiction of ASTM Committee E42 on Surface
difficult by virtue of:
Analysis and is the direct responsibility of Subcommittee E42.03 on Auger Electron
Spectroscopy and X-Ray Photoelectron Spectroscopy.
Current edition approved April 1, 2019. Published May 2019. Originally The last approved version of this historical standard is referenced on
approved in 1984. Last previous edition approved in 2018 as E983–10 (2018). DOI: www.astm.org.
10.1520/E0983–19. Available from International Organization for Standardization (ISO), ISO
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Geneva, Switzerland, http://www.iso.org.
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the references listed at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E983 − 19
A
TABLE 1 Electron Beam Damage in AES
5.1.1.1 Auger peak shift on energy scale,
Incident
5.1.1.2 Auger peak shape and size distortion, and
Beam Dc,
5.1.1.3 Auger signal strength instability. Material T Refs
4 2
Energy, 10 C/m
5.1.2 Electronic excitation of surface, subsurface, and bulk
keV
atoms and molecules leading to specimen changes (8-10)
Si N 2 stable . (25)
3 4
Al O 5103h (2)
2 3
which include:
Cu, Fe 1 1 15 min (26)
5.1.2.1 Dissociation,
Pthalocyanines
5.1.2.2 Electron stimulated desorption (ESD) (11), SiO 2 0.6 10 min (25)
Li WO 1 0.05 8 min (27)
5.1.2.3 Electron stimulated adsorption (ESA) (12), 2 4
NaF, LiF 0.1 0.06 60 s (22)
5.1.2.4 Polymerization (13, 14),
LiNO , LiSO 10.05 50s (27)
3 4
5.1.2.5 Carburization (15-17),
KCl 1.5 0.03 30 s (22)
TeO 20.02 20s (28)
5.1.2.6 Oxidation (18, 19),
H O(F) 1.5 0.01 10 s (29)
5.1.2.7 Reduction (20),
−3
Native oxides 5 2 × 10 2s (3)
−4
5.1.2.8 Decomposition (21, 22), C H (F) 0.1 3 × 10 0.3 s (30)
6 12
−4 −3
Na AlF 310 −10 0.1 s (31)
3 6
5.1.2.9 Erosion, and
−4
CH OH(F) 1.5 2.5 × 10 0.3 s (29)
5.1.2.10 Diffusion.
5.1.3 Charge accumulation in materials of poor electrical
A
conductivity leading to specimen changes which include (23,
where:
24, 7) (see Chapter 8):
D = critical dose for detectable damage,
c
5.1.3.1 Electric field enhanced diffusion, and
T = time of electron bombardment at 10A/m without detectable damage, and
5.1.3.2 Electromigration (4) (see p. 62). F = frozen.
(Adapted from Ref. 1.)
5.1.4 Heating which may cause:
5.1.4.1 Annealing,
5.1.4.2 Segregation,
5.1.4.3 Volatilization, and
5.1.4.4 Chemical reaction.
on a unit area of the specimen, expressed in coulombs per
square centimeter (C/cm ) (1).
6. Practical Manifestations of Electron Beam Effects
7.1.3 A number of materials, (for example, see Table 1),
6.1 Electron dose dependent changes in the intensity,
exhibit dose-dependent effects when the electron dose exceeds
energy, or peak shape of one or moreAuger transitions, or any
a material specific critical dose, D . The magnitude of the
c
combination thereof; depending upon the material, these
critical dose corresponds to the onset of detectable damage and
changes may be complete within a fraction of a second or they
the values may be subject to future revision. The material
may progress for hours. 2
specific critical dose, D , may be as low as 1 C⁄m .
c
6.2 Discoloration of the specimen in the proximity of the 7.1.4 In practice, the electron dose is directly dependent
electron beam irradiated region.
upon the electron beam current density, J , (A/m ), the time of
B
electron irradiation in seconds, t(s); and the angle of incidence,
6.3 Physical damage to the specimen such as erosion,
2 2
Θ, of the beam on the sample. That is, D (C/m )= J (A/m
C B
cracking, blistering, or densification.
)·t(s)·cosΘ. Using a typical electron beam current density,
2 -8
6.4 Pressure rises in the analytical vacuum chamber during
10 A⁄m would be equivalent to using 10 A incident beam
electron irradiation.
current into a 33 µm electron beam diameter at normal
6.5 Localized electric charge dependent changes in the incidence.
intensity, energy, or peak shape of allAuger transitions, or any 7.1.5 Theelectronbeam-inducedheatingofagivenmaterial
combination thereof. These changes may be stable but often of poor thermal conductivity and the accumulation of charge
are erratic resulting in unstable AES signals which may on a material of poor electrical conductivity are dependent
preclude AES data collection. upon the electron beam current density.
7.1.6 Current densities for a static electron beam should be
4 2
7. Electron Beam Parameters
of the order 10 A/m or less for susceptible materials. In the
7.1 Electron Dose and Current Density: case of rastered or gated electron beams, the time-averaged
current density and the instantaneous current density must be
7.1.1 Electron dose and current density were previously
2 2
defined using units of C/cm and mA/cm , respectively. These considered. Even though the time-averaged current density
units are not consistent with the SI system. To keep from may be small, the instantaneous current density may be
changing the magnitude of the numbers appearing in the sufficient to cause specimen damage or specimen charging.
literature (from which Table 1 is adapted), the multipliers of 7.1.7 In small-spot AES analysis, or scanning Auger
the terms are being changed. A dose of C/cm is equivalent to microscopy, the use of electron probes with high current
4 2 2 2
10 C/m , while 1mA/cm is equivalent to 10A/m . density is inherent. Obviously a trade-off between signal-to-
7.1.2 Specimenmaterialmodificationcanoftenberelatedto noiseandtheperturbingeffectsoftheelectronbeamisrequired
the electron dose (D); that is, the number of electrons incident (2).
E983 − 19
7.2 Electron Energy: acquisitions of Auger spectra during continuous electron irra-
7.2.1 The electron beam effects which involve electronic diation. However, if the change occurs within the acquisition
excitation are not strong functions of electron beam energies
time it will not be seen.
used for AES (1 keV to 25 keV). Changes in electron beam
9.2 If the specimen is a bulk insulator with a smooth
energywillaffectthedepth,andthereforethevolume,inwhich
surface, charging is generally reduced by decreasing the
such changes occur.
electron beam current, the current density (by defocusing the
7.2.2 Electron beam effects arising due to charging and
electron beam), lowering the accelerating voltage, and increas-
electric fields at the surface can be minimized by appropriate
ing the tilt angle (to increase electron emission). If the surface
empirical choices of the electron beam condition (accelerating
is rough, increased tilt angle may not help since the average
voltage, current, and current density). It
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E983 − 10 (Reapproved 2018) E983 − 19
Standard Guide for
Minimizing Unwanted Electron Beam Effects in Auger
Electron Spectroscopy
This standard is issued under the fixed designation E983; 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
1.1 This guide outlines the origins and manifestations of unwanted electron beam effects in Auger electron spectroscopy (AES).
1.2 Some general guidelines are provided concerning the electron beam parameters which are most likely to produce these
effects and suggestions are offered on how to minimize them.
1.3 General classes of materials are identified which are most likely to exhibit unwanted electron beam effects. In addition, a
tabulation of some specific materials which have been observed to undergo electron damage effects is provided.
1.4 A simple method is outlined for establishing the existence and extent of these effects during routine AES analysis.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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.
1.7 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.
2. Referenced Documents
2.1 ASTM Standards:
E673 Terminology Relating to Surface Analysis (Withdrawn 2012)
E996 Practice for Reporting Data in Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy
2.2 ISO Standard:
ISO 18115-1:2013 Surface chemical analysis -- Vocabulary -- Part 1: General terms and terms used in spectroscopy
3. Terminology
3.1 See TerminologyISO E67318115-1:2013 for terms used in Auger electron spectroscopy.
NOTE 1—Electron beam effects and their consequences are widely referred to in the literature using any one or more of the following terms: electron
beam damage, sample damage, specimen damage, beam effects, electron beam induced processes, and electron irradiation effects.
4. Significance and Use
4.1 When electron beam excitation is used in AES, the incident electron beam can interact with the specimen material causing
physical and chemical changes. In general, these effects are a hindrance to AES analysis because they cause localized specimen
modification (1-4).
This guide is under the jurisdiction of ASTM Committee E42 on Surface Analysis and is the direct responsibility of Subcommittee E42.03 on Auger Electron
Spectroscopy and X-Ray Photoelectron Spectroscopy.
Current edition approved Nov. 1, 2018April 1, 2019. Published November 2018May 2019. Originally approved in 1984. Last previous edition approved in 20102018 as
E983–10. –10 (2018). DOI: 10.1520/E0983–10R18.10.1520/E0983–19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
The boldface numbers in parentheses refer to the references listed at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E983 − 19
4.2 With specimens that have poor electrical conductivity the electron beam can stimulate the development of localized charge
on the specimen surface. This effect is a hindrance to AES analysis because the potentials associated with the charge can either
adversely affect the integrity of Auger data or make Auger data collection difficult (5, 6).
5. Origins of Electron Beam Effects
5.1 Electron beam effects in AES may originate from one or more distinct processes.
5.1.1 Charge accumulation (7) (see Chapter 9) in materials with poor electrical conductivity leading to potentials that cause
distortion of Auger data or make AES data collection difficult by virtue of:
5.1.1.1 Auger peak shift on energy scale,
5.1.1.2 Auger peak shape and size distortion, and
5.1.1.3 Auger signal strength instability.
5.1.2 Electronic excitation of surface, subsurface, and bulk atoms and molecules leading to specimen changes (8-10) which
include:
5.1.2.1 Dissociation,
5.1.2.2 Electron stimulated desorption (ESD) (11),
5.1.2.3 Electron stimulated adsorption (ESA) (12),
5.1.2.4 Polymerization (13, 14),
5.1.2.5 Carburization (15-17),
5.1.2.6 Oxidation (18, 19),
5.1.2.7 Reduction (20),
5.1.2.8 Decomposition (21, 22),
5.1.2.9 Erosion, and
5.1.2.10 Diffusion.
5.1.3 Charge accumulation in materials of poor electrical conductivity leading to specimen changes which include (23, 24, 7)
(see Chapter 8):
5.1.3.1 Electric field enhanced diffusion, and
5.1.3.2 Electromigration (4) (see p. 62).
5.1.4 Heating which may cause:
5.1.4.1 Annealing,
5.1.4.2 Segregation,
5.1.4.3 Volatilization, and
5.1.4.4 Chemical reaction.
6. Practical Manifestations of Electron Beam Effects
6.1 Electron dose dependent changes in the intensity, energy, or peak shape of one or more Auger transitions, or any
combination thereof; depending upon the material, these changes may be complete within a fraction of a second or they may
progress for hours.
6.2 Discoloration of the specimen in the proximity of the electron beam irradiated region.
6.3 Physical damage to the specimen such as erosion, cracking, blistering, or densification.
6.4 Pressure rises in the analytical vacuum chamber during electron irradiation.
6.5 Localized electric charge dependent changes in the intensity, energy, or peak shape of all Auger transitions, or any
combination thereof. These changes may be stable but often are erratic resulting in unstable AES signals which may preclude AES
data collection.
7. Electron Beam Parameters
7.1 Electron Dose and Current Density:
2 2
7.1.1 Electron dose and current density were previously defined using units of C/cm and mA/cm , respectively. These units are
not consistent with the SI system. To keep from changing the magnitude of the numbers appearing in the literature (from which
2 4 2 2
Table 1 is adapted), the multipliers of the terms are being changed. A dose of C/cm is equivalent to 10 C/m , while 1mA/cm is
equivalent to 10A/m .
7.1.2 Specimen material modification can often be related to the electron dose (D); that is, the number of electrons incident on
a unit area of the specimen, expressed in coulombs per square centimeter (C/cm ) (1).
7.1.3 A number of materials, (for example, see Table 1), exhibit dose-dependent effects when the electron dose exceeds a
material specific critical dose, D . The magnitude of the critical dose corresponds to the onset of detectable damage and the values
c
may be subject to future revision. The material specific critical dose, D , may be as low as 1 C ⁄m .
c
E983 − 19
A
TABLE 1 Electron Beam Damage in AES
Incident
Beam Dc,
Material T Refs
4 2
Energy, 10 C/m
keV
Si N 2 stable . (25)
3 4
Al O 5 10 3 h (2)
2 3
Cu, Fe 1 1 15 min (26)
Pthalocyanines
SiO 2 0.6 10 min (25)
Li WO 1 0.05 8 min (27)
2 4
NaF, LiF 0.1 0.06 60 s (22)
LiNO , LiSO 1 0.05 50 s (27)
3 4
KCl 1.5 0.03 30 s (22)
TeO 2 0.02 20 s (28)
H O(F) 1.5 0.01 10 s (29)
−3
Native oxides 5 2 × 10 2 s (3)
−4
C H (F) 0.1 3 × 10 0.3 s (30)
6 12
−4 −3
Na AlF 3 10 − 10 0.1 s (31)
3 6
−4
CH OH(F) 1.5 2.5 × 10 0.3 s (29)
A
where:
D = critical dose for detectable damage,
c
T = time of electron bombardment at 10A/m without detectable damage, and
F = frozen.
(Adapted from Ref. 1.)
F = frozen.
(Adapted from Ref. 1.)
7.1.4 In practice, the electron dose is directly dependent upon the electron beam current density, J , (A/m ), the time of electron
B
2 2
irradiation in seconds, t(s); and the angle of incidence, Θ, of the beam on the sample. That is, D (C/m ) = J (A/m )·t(s)·cosΘ.
C B
2 -8
Using a typical electron beam current density, 10 A ⁄m would be equivalent to using 10 A incident beam current into a 33 μm
electron beam diameter at normal incidence.
7.1.5 The electron beam-induced heating of a given material of poor thermal conductivity and the accumulation of charge on
a material of poor electrical conductivity are dependent upon the electron beam current density.
4 2
7.1.6 Current densities for a static electron beam should be of the order 10 A/m or less for susceptible materials. In the case
of rastered or gated electron beams, the time-averaged current density and the instantaneous current density must be considered.
Even though the time-averaged current density may be small, the instantaneous current density may be sufficient to cause specimen
damage or specimen charging.
7.1.7 In small-spot AES analysis, or scanning Auger microscopy, the use of electron probes with high current density is inherent.
Obviously a trade-off between signal-to-noise and the perturbing effects of the electron beam is required (2).
E983 − 19
7.2 Electron Energy:
7.2.1 The electron beam effects which involve electronic excitation are not strong functions of electron beam energies used for
AES (1 keV to 25 keV). Changes in electron beam energy will affect the depth, and therefore the volume, in which such changes
occur.
7.2.2 Electron beam effects arising due to charging and electric fields at the surface can be minimized by appropriate empirical
choices of the electron beam condition (accelerating voltage, current, and current density). It should be noted that the electron beam
angle of incidence (the angle between the electron beam and the specimen normal, as defined in Terminology E673) influences the
electron emission coefficient of the specimen surface and beam penetration depth.
8. Susceptible Materials
8.1 Nonmetallic Materials, particularly oxides, fluorides, chlorides, alkali halides, carbo
...