Field Emission Auger Electron Spectroscopy (AES)

A focused electron beam (3-20 keV) is scanned across the sample surface. Atoms near the surface are ionized, and a fraction of the ionized atoms relax via the Auger process. The spectrometer ultimately measures the kinetic energy distribution of a portion of the Auger electrons that are emitted from the sample. The technique is inherently surface sensitive because the majority of the measured Auger electrons originate in the outer 5-10 nm of the sample surface. The Auger spectra contain information about the concentration and chemical environment (i.e. oxidation state) of surface and near surface atoms. Greater depths (up to a few microns) can be probed by coupling the technique with ion milling. Lateral distributions of elements can be measured with sub-micron resolution. This instrument is essentially an FESEM that provides surface elemental and chemical sensitivity. The detection limits are roughly 0.1-1 atomic percent within the information depth.

Technique Advantages
  • surface sensitive (top 1-10 nm)
  • semi-quantitative without standards
  • exceptional spatial resolution
  • in-depth information available by ion beam depth profiling
Typical Applications
  • defects on semiconductors
  • grain boundary chemistry
  • failure analysis
  • interdiffusion
  • fracture mechanisms
  • surface/interface impurity determination
Sample Requirements

Any vacuum compatible conducting or semiconducting solid; thin insulators on conductors possible.

FEAES Instrumentation
  • 50 nm spatial resolution
  • autostage, autovalving
  • sample rotation stage (for enhanced depth resolution during profiling)
  • in situ fracture stage for metal fracture

* The FE Auger was purchased with the generous support of the National Science Foundation (DMR #0216779)