General Materials
ID #1019
Auger Electron Spectroscopy,Electron Spectroscopy
General Uses
· Compositional analysis of the 0- to 3-nm region near the surface for all elements except H and He
· Depth-compositional profiling and thin film analysis
· High lateral resolution surface chemical analysis and inhomogeneity studies to determine compositional
variations in areas ≥100 nm
· Grain-boundary and other interface analyses facilitated by fracture
· Identification of phases in cross sections
Examples of Applications
· Analysis of surface contamination of materials to investigate its role in such properties as corrosion,
wear, secondary electron emission, and catalysis
· Identification of chemical-reaction products, for example, in oxidation and corrosion
· In-depth compositional evaluation of surface films, coatings, and thin films used for various
metallurgical surface modifications and microelectronic applications
· Analysis of grain-boundary chemistry to evaluate the role of boundary precipitation and solute
segregation on mechanical properties, corrosion, and stress corrosion cracking phenomena
Samples
· Form: Solids (metals, ceramics, and organic materials) with relatively low vapor pressures (<10-8 torr at
room temperature). Higher vapor pressure materials can be handled by sample cooling. Similarly, many
liquid samples can be handled by sample cooling or by applying a thin film onto a conductive substrate
· Size: Individual powder particles as small as 1 μm in diameter can be analyzed. The maximum sample
size depends on the specific instrument; 1.5 cm (0.6 in.) in diameter by 0.5 cm (0.2 in.) high is not
uncommon
· Surface topography: Flat surfaces are preferable, but rough surfaces can be analyzed in selected small
areas (~ 1 μm) or averaged over large areas (0.5 mm in diameter)
· Preparation: Frequently none. Samples must be free of fingerprints, oils, and other high vapor pressure
materials
Limitations
· Insensitivity to hydrogen and helium
· The accuracy of quantitative analysis is limited to ±30% of the element present when calculated using
published elemental sensitivity factors (Ref 1). Better quantification (±10%)is possible by using
standards that closely resemble the sample
· Electron beam damage can severely limit useful analysis of organic and biological materials and
occasionally ceramic materials
· Electron beam charging may limit analysis when examining highly insulating materials
· Quantitative detection sensitivity for most elements is from 0.1 to 1.0 at.%
Estimated Analysis Time
· Usually under 5 min for a complete survey spectrum from 0 to 2000 eV. Selected peak analyses for
studying chemical effects, Auger elemental imaging, and depth profiling generally take much longer Capabilities of Related Techniques
· X-ray photoelectron spectroscopy: Provides compositional and chemical binding state information,
relatively nondestructive
· Ion scattering spectroscopy: Provides superb top atomic layer information, specificity of surface atomic
bonding in selected cases, and surface composition and depth profiling information
· Secondary ion mass spectroscopy: High elemental detection sensitivity from part per million to part per
billion levels; surface compositional information; depth profiling capability; sensitivity for all elements,
including hydrogen and helium
· Electron probe: Analysis to 1-μm depth in conventional operation, quantitative and nondestructive
· Analytical electron microscopy: Chemical analysis in conjunction with high-resolution microscopy Introduction
Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS),
and low-energy ion-scattering spectroscopy (LEISS), discussed in articles so named in this Volume, are among the most
widely used surface-sensitive analytical techniques capable of providing elemental composition of the outermost atomic
layer of a solid. These techniques are used to investigate the surface chemistry and interactions of solid surfaces of metals,
ceramics, organic materials, and biological materials. The techniques use electrons, x-rays, or ions as the probing sources,
and the surface chemical information is derived from analysis of electrons or ions emitted from the surface.
Auger electron spectroscopy and XPS involve precise measurements of the number of emitted secondary electrons as a
function of kinetic energy. Auger and photoelectron electrons, characteristic of the specific element emitting them, are
useful in qualitative analysis. Auger electrons were discovered in 1925.
· Compositional analysis of the 0- to 3-nm region near the surface for all elements except H and He
· Depth-compositional profiling and thin film analysis
· High lateral resolution surface chemical analysis and inhomogeneity studies to determine compositional
variations in areas ≥100 nm
· Grain-boundary and other interface analyses facilitated by fracture
· Identification of phases in cross sections
Examples of Applications
· Analysis of surface contamination of materials to investigate its role in such properties as corrosion,
wear, secondary electron emission, and catalysis
· Identification of chemical-reaction products, for example, in oxidation and corrosion
· In-depth compositional evaluation of surface films, coatings, and thin films used for various
metallurgical surface modifications and microelectronic applications
· Analysis of grain-boundary chemistry to evaluate the role of boundary precipitation and solute
segregation on mechanical properties, corrosion, and stress corrosion cracking phenomena
Samples
· Form: Solids (metals, ceramics, and organic materials) with relatively low vapor pressures (<10-8 torr at
room temperature). Higher vapor pressure materials can be handled by sample cooling. Similarly, many
liquid samples can be handled by sample cooling or by applying a thin film onto a conductive substrate
· Size: Individual powder particles as small as 1 μm in diameter can be analyzed. The maximum sample
size depends on the specific instrument; 1.5 cm (0.6 in.) in diameter by 0.5 cm (0.2 in.) high is not
uncommon
· Surface topography: Flat surfaces are preferable, but rough surfaces can be analyzed in selected small
areas (~ 1 μm) or averaged over large areas (0.5 mm in diameter)
· Preparation: Frequently none. Samples must be free of fingerprints, oils, and other high vapor pressure
materials
Limitations
· Insensitivity to hydrogen and helium
· The accuracy of quantitative analysis is limited to ±30% of the element present when calculated using
published elemental sensitivity factors (Ref 1). Better quantification (±10%)is possible by using
standards that closely resemble the sample
· Electron beam damage can severely limit useful analysis of organic and biological materials and
occasionally ceramic materials
· Electron beam charging may limit analysis when examining highly insulating materials
· Quantitative detection sensitivity for most elements is from 0.1 to 1.0 at.%
Estimated Analysis Time
· Usually under 5 min for a complete survey spectrum from 0 to 2000 eV. Selected peak analyses for
studying chemical effects, Auger elemental imaging, and depth profiling generally take much longer Capabilities of Related Techniques
· X-ray photoelectron spectroscopy: Provides compositional and chemical binding state information,
relatively nondestructive
· Ion scattering spectroscopy: Provides superb top atomic layer information, specificity of surface atomic
bonding in selected cases, and surface composition and depth profiling information
· Secondary ion mass spectroscopy: High elemental detection sensitivity from part per million to part per
billion levels; surface compositional information; depth profiling capability; sensitivity for all elements,
including hydrogen and helium
· Electron probe: Analysis to 1-μm depth in conventional operation, quantitative and nondestructive
· Analytical electron microscopy: Chemical analysis in conjunction with high-resolution microscopy Introduction
Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS),
and low-energy ion-scattering spectroscopy (LEISS), discussed in articles so named in this Volume, are among the most
widely used surface-sensitive analytical techniques capable of providing elemental composition of the outermost atomic
layer of a solid. These techniques are used to investigate the surface chemistry and interactions of solid surfaces of metals,
ceramics, organic materials, and biological materials. The techniques use electrons, x-rays, or ions as the probing sources,
and the surface chemical information is derived from analysis of electrons or ions emitted from the surface.
Auger electron spectroscopy and XPS involve precise measurements of the number of emitted secondary electrons as a
function of kinetic energy. Auger and photoelectron electrons, characteristic of the specific element emitting them, are
useful in qualitative analysis. Auger electrons were discovered in 1925.
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Last update: 2008-03-25 20:53
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