Scanning Auger Microanalysis (SAM)

Scanning auger microscopy (SAM) provides elemental and chemical composition for all elements with an atomic number greater than helium.  Its inherent sampling depth of 2-3 nanometers allows films as thin as a few monolayers to be analyzed.  SAM also maps the spatial distributions of elements and produces depth profiles of composition from 1 to 2,000 nanometers.

Applications: SAM applications include:

• Materials evaluation and identification
  • Surface contaminants
  • Surface homogeneity
  • Diffusion profiles
  • Particle sizes
  • Catalyst degradation
  • Interfaces

• Failure analysis
  • Corrosion characterization
  • Stain identification
  • Lifted lead bond evaluation
  • Material delamination analysis
  • Metal embrittlement evaluation

• Quality control screening
  • “Good-to-bad” sample comparison
  • Material and plating/coating thickness determination
  • Surface process modification

Principle of Operation

The sample is scanned with a focused beam of about 5 kilovolt electrons, causing low-energy Auger electrons to be ejected from its surface. The kinetic energies of these Auger electrons provide an analysis for the chemical elements present in the top few atomic layers. An auxiliary argon ion beam may be used to remove near-surface layers by “sputtering” to expose a fresh surface for analysis, producing a profile showing the dependence of sample composition on depth.