AES is used
to determine the atoms present at a surface, their concentrations, and their
lateral and depth distributions. Nano AES involves its application to the
analysis of very small regions of a surface, including nano-size particles.
Depth profiling of thin films will also be included.
•
Introduction –
terminology, surfaces, types of surfaces.
•
The principles of AES –
production of Auger electrons, peak labeling, ionization cross-sections,
handbooks, books, surface sensitivity, inelastic mean free path and databases,
information depth, sample handling.
•
Qualitative analysis – direct
and derivative spectra, identification of elements including examples using
software, energy resolution, peak widths, chemical effects on kinetic energy
and lineshapes, plasmons, cross transitions, ion-excited Auger transitions.
•
Quantitative analysis – Auger
intensities, sensitivity factors, detection limit, corrections for lineshape
changes, analyzer transmission, electron multiplier effects, matrix factors,
average matrix sensitivity factors, backscattering, effects of angle of
incidence and emission on quantitative analysis, standard spectra, diffraction
effects, signal-to-noise.
•
Artifacts – ionization loss peaks, electron beam damage.
•
Instrumentation – field
emission electron source, spatial resolution (beam), beam damage, cylindrical
mirror analyzer (CMA), hemispherical type analyzer (HSA), modes of operation,
electron detection, pulse counting, other electron sources, other types of
analyzers, scattering in analyzers, energy scale calibration, vacuum system,
samples.
•
Imaging and spatial resolution – scanning electron microscopy, acceptance
area of analyzers, locating regions of interest, corrections for topography and
backscattering, beam energy, spatial resolution (analysis), comparison of
analyzers, electron energy loss (EELS) imaging, ratioed scatter diagrams, line
scans, image registration, comparison
with EDS.
•
Data acquisition, processing and depth
profiling – spectrum subtraction, sputtering, crater edge
profiling, angle resolved AES, factor analysis, linear least squares fitting,
sample rotation, mechanical methods. Examples of data processing methods to
remove peak overlap problems, separate different chemical states, and improve
signal-to-noise in sputter depth profiles will be demonstrated.
•
Insulating samples –
charge control methods, effects on images and spectra, use of low energy ion
beam.
•
Applications – nano analysis of spheres, particles, via holes,
insulators, sputter depth profiles of nanolayers.
•
Instrument selection and summary – factors to consider, general summary.