TOF SIMS

  • Time-of-flight Secondary Ion Mass Spectrometry is a versatile instrument capable of parts-per-million sensitivity or better with parallel detection for nearly all elements and molecules up to several thousand atomic mass units.
  • Mass resolved imaging provides mapping with lateral resolution better than 150nm.
  • Surface analysis sensitivity is comparable to TXRF, though it also provides lower mass range sensitivity and targeting of smaller areas.
  • Depth profiling with sputter ion guns can be optimized for low energy ultra-shallow implants or for several micron deep layers.

Strengths Limitations

- Parallel mass detection up to 10,000 amu Part-per-million sensitivity
- Retrospective region-of-interest analysis
- Lateral image resolution down to 100 nm

- Time consuming data processing
- Surface analysis requires proper sample handling
- Volatile materials may sublime in UHV
- Requires standards for quantification


Courtesy of ION-TOF GmbH


Demo of pulsed Bi+ primary ion gun and parallel detection of secondary ions from a sample


Demo of Bi+ primary ion impacting sample surface, and secondary ions escaping


3D depth profile of Mo ions in semiconductor device


Depth profile overlay of three masses (green, red, and blue) showing cell concentrations


Depth profile of shallow B implant into Si wafer with 6 orders of dynamic range with detection limit below 1E16 at/cc


Secondary mass spectrum of Fe+ and molecular ions with mass resolution >10,000


More information: http://en.wikipedia.org/wiki/Time-of-flight_mass_spectrometry