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. Sputter depth profiles of thin films will also be included.
Topics of this course:
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.
Ionization loss peaks, electron beam damage.
Field emission electron source, spatial resolution (beam), signal-to-noise, 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.
- 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 and instrument selection