Analysis by the Detection of Scattered Ions

Analysis by the Detection of Scattered Ions. Ions generally penetrate the specimen much less deeply than electrons of equivalent energy, so they are more surface-sensitive. Ion-based surface analytical techniques are popular because of their sensitivity and their ability, in some cases, to reveal the depth composition profile. 

SIMS has the principal advantage of high surface sensitivity (only a very small proportion of the detected ions come from the second or lower layers of the material being analysed) and its very low detection limits for impurities. All elements can be detected at concentrations of ppm ( 0.0001%) in the surface region. This may be contrasted with AES or XPS where the detection limit is 0.1% with a sampling 

Technique Detection Lateral resolution Min. cone, detected Element range Chemical state info. Quantitative 

EELS Electrons Atomic level Atomic level Esp. Z 10 Yes Yes 

SIMS Ions 20 nm-1 jim depending on ion source Ppm for most elements Ppb for most favourable All elements isotopes distinguishable Yes Not in general, but internal standards usable in some cases. 

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