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Secondary Ion Mass Spectrometry

SIMS

Secondary Ion Mass Spectrometer (SIMS), used for for surface molecular or elemental analysis, trace element depth profiling, and secondary ion microscopy. This instrument provides true elemental and stable isotopic analysis with high mass resolution and high sensitivity (parts per billion detection limits). The ion probe is optimized for rare earth elements and stable isotopes (H, C, N, O, S) analysis of natural and synthetic materials. It can be used to provide a 3-dimensional chemical analysis profile from a surface into the bulk of a solid with sub-micron spatial resolution.

Secondary ion mass spectrometry (SIMS) offers elemental depth profile by sputtering the surface of the specimen with a beam of primary ions; the ejected secondary ions are collected and analyzed using a mass spectrometer, providing elemental, isotopic or molecular composition over a wide depth range from a few angstroms to tens of micrometers. With its ppm-ppb detection sensitivity, SIMS is commonly used to detect very low concentrations of impurities and dopants.

APPLICATIONS

  • Dopant and impurity measurements with ppm-ppb detection sensitivity
  • Compositional analysis of thin films with ultra-high depth resolution
  • Detection of all elements and isotopes

LIMITATIONS

  • Vacuum compatibility required
  • Destructive technique
  • Chemical bonding information unavailable

 

SIMS

SIMS: Cameca IMS 7f GEO

The Cameca IMS 7f GEO is a magnetic sector Secondary Ion Mass Spectrometer for surface molecular or elemental analysis, trace element depth profiling, and secondary ion microscopy. This instrument provides true elemental and stable isotopic analysis with high mass resolution and high sensitivity (parts per billion detection limits). The ion probe is optimized for rare earth elements and stable isotopes (H, C, N, O, S) analysis of natural and synthetic materials. It can be used to provide a 3-dimensional chemical analysis profile from a surface into the bulk of a solid with sub-micron spatial resolution.

TECHNICAL SPECIFICATIONS

  • Signal Detected: Secondary ions
  • Elements Detected: H-U including isotopes
  • Detection Limits: >1E10 to 1E16 atoms/cm3
  • Depth Resolution: >5 Å
  • Imaging/Mapping: Yes
  • Lateral Resolution/Probe Size: ≥10 µm (depth profiling); 1 µm (imaging mode)

Detailed Specifications

The NCFL’s Cameca IMS 7f GEO is equipped with:

  • High throughput: transmission through magnetic sector analyzer is two orders of magnitude higher than that of quadrupole analyzers.
  • Primary ion column has real-time beam current monitoring for improved depth scale accuracy.
  • Computer controlled apertures and slit movement with storable settings; automated analyses.
  • Optical system for direct ion microscopy and scanning microprobe modes of operation.
  • Ion impact energy can be reduced to very low level (300 eV), with independent control of the impact angle by the continuous variation of extraction voltage and primary energy.
  • High speed of erosion (2 nm/min with 500 eV O2+, 45 degrees on silicon) can be maintained at low energy.
  • Electron flood gun makes it possible to measure depth profiles on complex insulating structures.
  • Optical system allows a mass resolution up to 25 000 (at 10% definition, equivalent at least to 50 000 FWHM as quoted for TOF-SIMS); removes most mass interferences.
  • Double focusing analyser with adjustable energy slit allows energy filtering of the secondary ions to reduce contribution from different species at the same nominal mass.
  • Dual FC detection and fast electro-magnetic peak switching for high sample throughput (10 to 50 times greater for stable isotopes than IMS 7f).

Publications with NanoEarth that acknowledge NSF.

Training modules, videos, sample prep, etc.