ASTM E1078-14(2020)

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: E1078 − 14 (Reapproved 2020)
Standard Guide for
Specimen Preparation and Mounting in Surface Analysis
This standard is issued under the fixed designation E1078; 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 E1127 Guide for Depth Profiling in Auger Electron Spec-
troscopy
1.1 This guide covers specimen preparation and mounting
E1523 Guide to Charge Control and Charge Referencing
prior to, during, and following surface analysis and applies to
Techniques in X-Ray Photoelectron Spectroscopy
the following surface analysis disciplines:
E1829 Guide for Handling Specimens Prior to Surface
1.1.1 Auger electron spectroscopy (AES),
Analysis
1.1.2 X-ray photoelectron spectroscopy (XPS and ESCA),
2.2 ISO Standards:
and
ISO 18115–1 Surface chemical analysis—Vocabulary—Part
1.1.3 Secondary ion mass spectrometry (SIMS).
1: General terms and terms used in spectroscopy
1.1.4 Although primarily written forAES, XPS, and SIMS,
ISO 18115–2 Surface chemical analysis—Vocabulary—Part
these methods will also apply to many surface sensitive
2: Terms used in scanning-probe microscopy
analysis methods, such as ion scattering spectrometry, low
energy electron diffraction, and electron energy loss
3. Terminology
spectroscopy, where specimen handling can influence surface
sensitive measurements.
3.1 Definitions—For definitions of surface analysis terms
used in this guide, see ISO 18115-1 and ISO 18115-2.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
4. Significance and Use
standard.
4.1 Proper preparation and mounting of specimens is par-
1.3 This standard does not purport to address all of the
ticularly critical for surface analysis. Improper preparation of
safety concerns, if any, associated with its use. It is the
specimens can result in alteration of the surface composition
responsibility of the user of this standard to establish appro-
and unreliable data. Specimens should be handled carefully so
priate safety, health, and environmental practices and deter-
as to avoid the introduction of spurious contaminants in the
mine the applicability of regulatory limitations prior to use.
preparation and mounting process. The goal must be to
1.4 This international standard was developed in accor-
preserve the state of the surface so that the analysis remains
dance with internationally recognized principles on standard-
representative of the original.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4.2 AES, XPS or ESCA, and SIMS are sensitive to surface
mendations issued by the World Trade Organization Technical layers that are typically a few nanometres thick. Such thin
Barriers to Trade (TBT) Committee. layers can be subject to severe perturbations caused by
specimen handling (1) or surface treatments that may be
2. Referenced Documents
necessary prior to introduction into the analytical chamber. In
addition, specimen mounting techniques have the potential to
2.1 ASTM Standards:
affect the intended analysis.
E983 Guide for Minimizing Unwanted Electron Beam Ef-
fects in Auger Electron Spectroscopy
4.3 This guide describes methods that the surface analyst
may need to minimize the effects of specimen preparation
when using any surface-sensitive analytical technique. Also
This guide is under the jurisdiction of ASTM Committee E42 on Surface
described are methods to mount specimens so as to ensure that
Analysis and is the direct responsibility of Subcommittee E42.03 on Auger Electron
the desired information is not compromised.
Spectroscopy and X-Ray Photoelectron Spectroscopy.
Current edition approved Dec. 1, 2020. Published December 2020. Originally
approved in 1990. Last previous edition approved in 2014 as E1078 – 14. DOI:
10.1520/E1078-14R20. 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 service@astm.org. 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 a list of references 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
E1078 − 14 (2020)
4.4 Guide E1829 describes the handling of surface sensitive 6.1.2 Special caution must be taken with specimens con-
specimens and, as such, complements this guide. taining potential toxins.
6.2 Information Sought—The information sought can influ-
5. General Requirements
ence the preparation of a specimen. If the information sought
5.1 Although the handling techniques for AES, XPS, and comesfromtheexteriorsurfaceofaspecimen,greatercareand
SIMS are basically similar, there are some differences. In precautions in specimen preparation must be taken than if the
general, preparation of specimens for AES and SIMS requires information sought lies beneath an overlayer that must be
more attention because of potential problems with electron or sputtered away in the analytical chamber. Furthermore, it may
ion beam damage or charging, or both. This guide will note also be possible to expose the layer of interest by in-situ
when specimen preparation is significantly different among the fracture, cleaving, or other means.
three techniques.
6.3 Specimens Previously Examined by Other Analytical
5.2 The degree of cleanliness required by surface sensitive
Techniques—It is best if surface analysis measurements are
analyticaltechniquesisoftenmuchgreaterthanforotherforms
made before the specimen is analyzed by other analytical
of analysis.
techniques because such specimens may become damaged or
may be exposed to surface contamination. For example,
5.3 Specimensandmountsmustneverbeincontactwiththe
insulating specimens analyzed by electron microscopy may
bare hand. Handling of the surface to be analyzed should be
have been coated to reduce charging. This coating will render
eliminated or minimized whenever possible. Fingerprints con-
the specimen unsuitable for subsequent surface analysis.
tain mobile species that may contaminate the surface of
Furthermore, exposure to an electron beam (for example, in a
interest. Hand creams, skin oils, and other skin materials are
SEM) can induce damage or cause the adsorption and deposi-
not suitable for high vacuum.
tion of species from the residual vacuum. If it is not possible to
5.4 Visual Inspection:
perform surface analysis first, then the analysis should be done
5.4.1 Avisual inspection should be made, possibly using an
on a different, but nominally identical, specimen or area of the
optical microscope, prior to analysis. At a minimum, a check
specimen.
should be made for residues, particles, fingerprints, adhesives,
contaminants, or other foreign matter.
7. Sources of Specimen Contamination
5.4.2 Features that are visually apparent outside the vacuum
7.1 Tools, Gloves, Etc.:
system may not be observable with the system’s usual imaging
7.1.1 Preparation and mounting of specimens should only
method or through available viewports. It may be necessary to
be done with clean tools to ensure that the specimen surface is
physically mark the specimen outside the area to be analyzed
not altered prior to analysis and that the best possible vacuum
(forexample,withscratchesorapermanentinkmarker)sothat
conditionsaremaintainedintheanalyticalchamber.Toolsused
the analysis location can be found once the specimen is inside
to handle specimens should be made of materials that will not
the vacuum system.
transfer to the specimen or introduce spurious contaminants
5.4.3 Changesthatmayoccurduringanalysismayinfluence
(for example, nickel tools contaminate silicon). Tools should
the data interpretation. Following analysis, visual examination
be cleaned in high purity solvents and dried prior to use.
of the specimen is recommended to look for possible effects of
Nonmagnetic tools should be used if the specimen is suscep-
sputtering, electron beam exposure, X-ray exposure, or
tibletomagneticfields.Toolsshouldneverunnecessarilytouch
vacuum.
the specimen surface.
7.1.2 Although gloves and wiping materials are sometimes
6. Specimen Influences
used to prepare specimens, it is likely that their use may result
6.1 History—The history of a specimen may affect the
in some contamination. Care should be taken to avoid con-
handling of the surface before analysis. For example, a
tamination by talc, silicone compounds, and other materials
specimen that has been exposed to a contaminating environ-
that are often found on gloves. “Powder-free” gloves have no
ment may reduce the need for exceptional care if the surface
talc and may be better suited. Unnecessary contact with the
becomes less reactive. Alternatively, the need for care may
glove or other tool shall be avoided.
increase if the surface becomes toxic.
7.1.3 Specimen mounts and other materials used to hold
6.1.1 If a specimen is known to be contaminated, preclean-
specimens should be cleaned regularly whenever there is a
ing may be warranted in order to expose the surface of interest
possibility of cross-contamination of specimens.Avoid the use
and reduce the risk of vacuum system contamination. If
of tapes containing silicones and other mobile species.
precleaning is desired, a suitable grade solvent should be used
that does not affect the specimen material (electronic grade 7.2 Particulate Debris—Blowing one’s breath on the speci-
solvents if appropriate or available are best suited). Note that men is likely to cause contamination. Compressed gases from
even high purity solvents may leave residues on a surface. aerosol cans or from air lines are often used to blow particles
Cleaning may also be accomplished using an appropriately from the surface or to attempt to clean a specimen. They, too,
filtered pressurized gas. In some instances, the contamination must be considered a source of possible contamination. While
itself may be of interest, for example, where a silicone release particles are removed from specimens by these methods,
agent influences adhesion. In these cases, no precleaning caution is advised and the methods should be avoided in
should be attempted. critical cases. In particular, oil is often a contaminant in
E1078 − 14 (2020)
compressed air lines. In-line particle filters can reduce oil and 7.5.4 In SIMS, atoms sputtered onto the secondary ion
particles from these sources. A gas stream can also produce extractionlensorothernearbysurfacescanberesputteredback
static charge in many specimens, and this could result in onto the surface of the specimen.This effect can be reduced by
attraction of more particulate debris. Use of an ionizing nozzle not having the secondary ion extraction lens or other surfaces
on the gas stream may eliminate this problem. close to the specimen. The use of multiple immersion lens
strips or cleaning of the lens can help reduce this effect.
7.3 Vacuum Conditions and Time—Specimens that were in
7.5.5 The order of use of probing beams can be important,
equilibrium with the ambient environment prior to insertion
especially when dealing with organic material or other fragile
into the vacuum chamber may desorb surface species, such as
materials (such as those discussed in Section 12).
water vapor, plasticizers, and other volatile components. This
may cause cross-contamination of adjacent samples and may
8. Specimen Storage and Transfer
increase the chamber pressure. It also may cause changes in
8.1 Storage:
surface chemistry of the specimens of interest.
8.1.1 Time—The longer a specimen is in storage, the more
7.4 Effects of the Incident Flux:
caremustbetakentoensurethatthesurfacetobeanalyzedhas
7.4.1 The incident electron flux in AES, ion flux in SIMS,
notbeencontaminated.Evenincleanlaboratoryenvironments,
and, to a lesser extent, the photon flux in XPS, may induce
surfaces can quickly become contaminated to the depth ana-
changes in the specimen being analyzed (2), for example by
lyzed byAES, XPS, SIMS, and other surface sensitive analyti-
causing enhanced reactions between the surface of a specimen
cal techniques.
and the residual gases in the analytical chamber. The incident
8.1.2 Containers:
flux also may locally heat or degrade the specimen, or both,
8.1.2.1 Containers suitable for storage should not transfer
resulting in a change of surface chemistry or a possible rise in
contaminants to the specimen by means of particles, liquids,
chamber pressure and in contamination of the analytical
gases, or surface diffusion. Keep in mind unsuitable containers
chamber. These effects are discussed in Guide E983.
may contain volatile species, such as plasticizers, that may be
7.4.2 Residual gases or the incident beam may alter the
emitted, contaminating the surface. Preferably, the surface to
surface. One can test for undesirable effects by monitoring
be analyzed should not contact the container or any other
signalsfromthespecimenasafunctionoftime,forexampleby
object. Glass jars with an inside diameter slightly larger than
setting up the system for a sputter depth profile and then not
the width of a specimen can hold a specimen without contact
turning on the ion gun. If changes with time are observed, then
withthesurface.Whencontactwiththesurfaceisunavoidable,
the interpretation of the results must account for the observa-
wrapping in clean, pre-analyzed aluminum foil may be satis-
tion of an altered surface. This method may also detect
factory. Containers with a beveled bottom may also be appro-
desorption of surface species. Care should be taken to account
priateforstoringflatspecimens(facedowntowardthebevelso
for the possible effects of incident beam fluctuation.
that only the edges of the sample touch the container).
7.4.3 The incident ion beams used during SIMS, AES, and
8.1.2.2 Containers such as glove boxes, vacuum chambers,
XPS depth profiles not only erode the surface of interest but
and desiccators may be excellent choices for storage of
can also affect surfaces nearby. This can be caused by poor
specimens. A vacuum desiccator may be preferable to a
focusing of the primary ion beam and impact of neutrals from
standard unit and should be maintained free of grease and
theprimarybeam.Theseadjacentareasmaynotbesuitablefor
mechanical pump oil. Cross-contamination between specimens
subsequent analysis by surface analysis methods. In some
may also occur if multiple specimens are stored together.
cases, sputtered material may be deposited onto adjacent areas
8.1.3 Temperature and Humidity—Possible temperature and
on the specimen or onto other specimens that may be in the
humidityeffectsshouldbeconsideredwhenstoringorshipping
analytical chamber.
specimens. Most detrimental effects result from elevated tem-
peratures.Additionally,lowspecimentemperaturesandhighto
7.5 Analytical Chamber Contamination:
moderate humidity can lead to moisture condensation on the
7.5.1 The analyst should be alert to materials that will lead
surface.
to contamination of the vacuum chamber as well as other
specimens in the chamber. High vapor pressure elements such
8.2 Transfer:
as mercury, tellurium, cesium, potassium, sodium, arsenic,
8.2.1 Chambers—Chambers that allow transfer of speci-
iodine, zinc, selenium, phosphorus, sulfur, etc. should be
mens from a controlled environment to an analytical chamber
analyzed with caution. Many other materials also can exhibit
have been reported (4-6). Controlled environments could be
highvaporpressures;theseincludesomepolymers,foams,and
other vacuum chambers, glove boxes (dry boxes), glove bags,
other porous materials, greases and oils, and liquids.
reaction chambers, etc. Controlled environments can be at-
7.5.2 Even if an unperturbed specimen meets the vacuum
tached directly to an analytical chamber with the transfer made
requirements of the analytical chamber, the probing beam
through a permanent valve. Glove bags can be temporarily
required for analysis may degrade the specimen and result in attached to an analytical chamber with transfer of a specimen
serious contamination, as discussed in 7.4.1.
done by removal and then replacement of a flange on the
analytical chamber.
7.5.3 Contamination by surface diffusion can be a problem,
especially with silicone compounds (3) and hydrocarbons. It is 8.2.2 Coatings—Coatings can sometimes be applied to
possible to have excellent vacuum conditions in the analytical specimens allowing transfer in atmosphere.The coating is then
chamber and still find contamination by surface diffusion. removedbyheatingorvacuumpumpingineithertheanalytical
E1078 − 14 (2020)
chamber or its introduction chamber. This concept has been 9.3.3 Transfer of Particles—Particles may sometimes be
successfully applied to the transfer of GaAs (7). Surfaces to be transferred to a suitable substrate by working under a micro-
analyzedbySIMSorAEScanbecoveredwithauniformlayer, scope and by using a very sharp needle. Non-soluble particles
such as polysilicon for silicon-based technology (8). In this may sometimes be floated on solvents and picked up on
case, the coating is removed during analysis, however the conducting filters. Particles can also be transferred onto adhe-
influence of atomic mixing on the data must be considered. sive tape or replicating compound as discussed in Guide
E1829.
9. General Mounting Procedures
9.4 Wires, Fibers, and Filaments—Wire, fibers, and fila-
9.1 In general, the specimen will be analyzed as received.
mentsmaybeofsuchsizethatitisnotpossiblefortheprobing
Surface contamination or atmospheric adsorbates are not
beamtoremainonthespecimenonly,andbackgroundartifacts
usually removed from such specimens because of the impor-
may result. In such instances, it may be possible to mount the
tance of analyzing an unaltered surface. In such cases, the
specimen such that the background is sufficiently out of focus
specimen should be mounted directly to the specimen mount
so that it does not contribute to the signal (for example, the
and held down with a clip or screw. Care should be taken to
sample might be mounted over a hole). Alternatively, many
ensure that the clip or screw does not contact the surface of
wires, fibers, or filaments can also be placed side-by-side or
interest and that it will not interfere with the analysis probes. If
bundledtofillthefieldofview.Insomecases,thesespecimens
specimen charging is a concern, the clip or screw can help to
may be mounted like powders and particles (see 9.3).
provide a conductive path to ground.
9.5 Pedestal Mounting—For some analytical systems, espe-
9.2 For some specimens, it is easier to mount the sample by
cially those with large analysis areas, it is possible to mount a
pressing it into a soft metal foil or by placing it on the sticky
specimen on a pedestal so that only the specimen will be seen
surfaceofadhesivetape.Thefoilortapeisthenattachedtothe
by the analyzer. This approach may allow analysis of speci-
specimen holder. Double-sided tape has the advantage of not
mens that are smaller than the analysis area.
requiring a clip or screw to hold it onto the specimen mount.
Care should be taken to ensure that the surface to be analyzed 9.6 Methods of Reducing Charging:
doesnotcomeintocontactwiththefoilortape.Alltapeshould
9.6.1 General Considerations—Specimen charging can be a
be pretested for vacuum compatibility and potential contami-
serious problem with poorly conducting specimens. For many
nation.
specimens, charging problems are usually more severe with
incident electron or ion beams than with an incident X-ray
9.3 Powders and Particles:
beam. In XPS, charging is usually more severe for a focused
9.3.1 Substrates—Powders and particles are often easier to
monochromatic X-ray beam than for a large-area beam or
analyze if they are placed on a conducting substrate. Indium
non-monochromatic X-rays. If the surface is heterogeneous or
foil is often used because it is soft at room temperature and
the probing radiation is focused, the amount of charging can
powders or particles will imbed partly into the foil. (Aproblem
differ across the detection area. Additional reviews of charge
withindiumfoilisthatitredeposits,ifsputteringisattempted.)
controlandchargereferencingtechniquesinXPScanbefound
Aluminum, copper, and other metal foils can be used, though
in Guide E1523.
only a small percentage of the powder particles may adhere to
them. For XPS, powders can be placed on the sticky side of 9.6.2 Conductive Mask, Grid, Wrap, or Coating—A mask,
adhesive tape (see 9.2). Metallized tape is usually best and can grid, wrap, or coating of a conducting material can be used to
meet the vacuum requirements of most XPS systems. If any cover insulating specimens and make contact to ground as
adhesive tape is used, it should be pretested for vacuum closeaspossibletothesurfacethatwillbeanalyzed.Agridcan
compatibility and potential contamination. For some materials alsobesuspendedslightlyaboveasurface (10).Wrapsofmetal
pressing a powder into a pliable substrate such as clean room foils have been used for the same purpose. In AES, it may be
paper tissue could be considered as an alternative, but the
important to cover insulating areas of the specimen that are not
substrate must be pretested for vacuum compatability and for in the immediate area of analysis so as to avoid the accumu-
potential contamination. lation of scattered electrons and ions that could build up
9.3.2 Pellets—Many powders can be formed into pellets enoughchargetodeflecttheelectronprobebeamtoorfromthe
without the use of sintering aids.Alternatively, compression of specimen and perturb the analysis accordingly. Whenever
the powder into a disk such as is used for preparation of KBr sputtering is used in conjunction with a mask, grid, or wrap,
disks for infrared spectroscopy can be used. The resulting care should be taken to ensure that material is not sputtered
surface is then gently abraded with a clean scalpel blade prior from the covering material onto the surface of the specimen.
to use. Forming pellets can be an excellent approach for XPS Removable grids have been reported that allow the grid to be
but often leads to specimen charging in AES and SIMS. Note movedduringsputteringperiodsandreturnedforanalysis (11).
that pressure and temperature-induced changes may occur. Materials such as colloidal silver, silver epoxy, or colloidal
Alternatively, mixing powder with silver flake then polishing graphitecanbeusedtoprovideaconductingpathfromnearthe
afterwards has been very successful although the outside of the pointofanalysistoground;however,bewarethatoutgassingof
powder grain is sacrificed.With electron beam excitation, even the solvent or of the conductive paint may cause a problem.
insulating powders can be analyzed this way as the powder Coating a specimen with a thin conducting layer and subse-
grain is surrounded by a conductive medium which is also a quently removing the coating by sputtering may be useful, but
good heat sink (9). information regarding the topmost layer of the specimen will
E1078 − 14 (2020)
generally be lost.This approach can be useful for sputter depth 9.7 Methods of Reducing Thermal Damage—To reduce
profiling with the warning that charging may reappear as the thermal damage, specimens can be mounted on a cold probe or
stagewithliquidnitrogenorothercoldliquidsorgasesflowing
layers are removed if the walls of the crater remain electrically
insulating. Combinations of coatings and masks or wraps may through it. Some specimens such as powders could benefit
from being compacted to pellets, thereby increasing heat
be used.
dissipation. Good thermal contact between the specimen and
9.6.3 Flood Gun—Low-energy electrons from a nearby
the mounting system should be considered. Wrapping a speci-
filament can be useful for reducing charging of specimens in
men in a metal foil may be of value in some cases. Reducing
XPS. The window material in a conventional X-ray source can
the energy input during analysis would also be beneficial as
also act as a source of electrons to reduce charging. Relative
discussed in 9.6.5.2 and 9.6.5.3, but this may result in longer
location of electron and ion optics in SIMS analysis of
data acquisition times.
insulators can influence charging phenomena (12, 13). Positive
ion SIMS depth profiling requires the use of a focused electron
10. Techniques for Specimen Preparation
beam with similar or greater current density to the ion beam.
Negative ion primary beams may be used. A low energy ion 10.1 General Considerations:
10.1.1 Often the surface or interface of interest lies beneath
flood gun may also be used to minimize charging in AES.
a layer of contaminants or other constituents. The problem is
9.6.4 In XPS, selecting an area of analysis within an area
then to remove the overlayer without perturbing the surface or
that is uniformly charged will help to minimize surface
interface of interest.
charging. Note that this approach, however, may select an area
10.1.2 For electronic devices, additional information re-
with properties that are different from adjacent areas.
garding preparation of specimens can be found in (17).
9.6.5 Incident Electron and Ion Beams:
10.2 Mechanical Separation—Sometimes it is possible to
9.6.5.1 Angle of Incidence—The secondary electron emis-
mechanicallyseparatelayersandexposethesurfaceofinterest.
sion coefficient and the incident beam current density are
Except for possible reactions with the atmosphere, a surface
functions of the angle of incidence of the primary electron
exposedinthiswayisgenerallyexcellentforanalysis.Delami-
beam. Grazing angles of incidence increase the secondary
nating layers and the inside surfaces of blister-like structures
electron emission coefficient and are, therefore, generally
are often investigated in this way. Sputter depth profiling is
better for reduction of charging during AES analysis of flat
generallynotagoodmethodtouseonblister-likestructures.At
specimens (14-16).
thepointwhentheouterskinispenetratedbytheionbeam,the
9.6.5.2 Energy—The secondary electron emission coeffi-
data may become dominated by artifacts. Mechanical separa-
cient is also a function of the energy of the incident electron
tion should be carried out just prior to transfer of the sample to
beam. Generally, incident energies where the secondary elec-
the analytical instrument, or in-situ if possible.
tron emission coefficient is greater than unity are better for
10.3 Thinning Versus Removal—Complete removal of an
reducing specimen charging. This usually means that the
overlayer may not be possible or desirable. It may be sufficient
incident beam energy will have to be lowered, perhaps even as
to thin the overlayer and continue using sputter depth profiling
low as 1 keV, to eliminate charging and obtain useful Auger
as discussed in 10.9.
yields. For some layered specimens, it might be possible to
achievereducedspecimenchargingbyincreasingtheenergyof
10.4 Removing the Substrate—In some specimens, it may
the incident electron beam such that penetration is made to a
be easier to approach the interface of interest by removing the
conducting layer beneath the layer being analyzed. This will
substrate rather than the overlayer, for example, when the
result in charge neutralization through the insulating layer to
composition of the substrate is not of interest, and the compo-
the conducting layer if the conducting layer is suitably
sition of the overlayer material is unknown. Chemical etches
grounded. In SIMS, the energy of the incident ion affects
may be used more effectively and perhaps selectively when the
specimen charging (12).
composition of the material to be etched is known. In SIMS, if
the overlayers are characterized by nonuniform sputtering,
9.6.5.3 Current Density—Specimen charging may be re-
substrateremovalmayprovideimproveddepthresolution (18).
ducedbydecreasingthecurrentdensityoftheincidentelectron
As discussed in 10.3, complete removal of the substrate may
orionbeam.Reductionofthebeamdensitycanbeachievedby
not be necessary.
reducing the total current, defocusing the beam, rastering the
beam over a part of the specimen surface, or by changing the
10.5 Sectioning Techniques:
angle of incidence.
10.5.1 General—Sectioning (cutting) is most often applied
9.6.5.4 Concurrent Electron and Ion Beams—If a specimen
to metals, but it can often be applied to other materials equally
is homogeneous with depth, charging in AES analysis some-
well. When using sectioning techniques, it is important to
times can be reduced by sputtering the specimen during section such that minimum alteration occurs to the region of
analysis. The in
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