The material's surface is quite important. To achieve good results, numerous efforts are currently concentrated on controlling chemical reactions on the surface of materials. Surface chemistry modification will necessitate comprehensive surface characterization to ensure that the required changes have been made. This will include the capacity to determine surface molecule and chemical structure composition, structure, orientation, and spatial distribution.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful surface characterization technique that can meet these requirements through spectroscopic analysis and direct chemical state imaging. Alfa Chemistry can do surface chemical composition analysis using time of flight secondary ion mass spectrometry. We can give chemical and distribution (lateral and depth) information for diverse materials and applications based on its outstanding mass resolution, sensitivity, and high spatial resolution.
Learn About ToF-SIMS
ToF-SIMS removes compounds from the surface of the material using a pulsed ion beam (Cs or micro-focused Ga). Particles are removed from the surface's monolayer of atoms (secondary ions). The mass of these particles is estimated by monitoring the precise time they arrive at the detector after they are accelerated into the "flight tube" (i.e. time of flight). Using ToF-SIMS can use three operating modes: surface spectroscopy, surface imaging and depth profiling.
ToF-SIMS study results under typical operational circumstances include:
- A mass spectrum that can measure all atomic masses in the range of 0-10000 amu;
- The grating beam provides a map of any quality of interest on the sub-micron scale;
- The depth profile is created by removing the surface layer by sputtering under an ion beam.
Because of the low primary ion current utilized to "scratch" the sample surface to release ions, molecules, and molecular clusters for analysis, ToF-SIMS is also known as "static" SIMS. For quantitative investigation, however, "dynamic" SIMS is recommended since greater primary ion currents result in faster sputtering rates and higher ion yields. As a result, dynamic SIMS can produce more accurate trace element counting statistics.
ToF-SIMS of Alfa Chemistry
We use the ToF-SIMS method to clearly and highly sensitively identify the atomic and molecular composition of the outermost layer 1-3 of the material. This approach has an even higher sensitivity than XPS. The fine spatial resolution is another advantage of this approach. This method can be used to examine solid and powder samples of any substance.
Fig 1. Schematic for analysis of a surface by time-of-flight secondary ion mass spectrometry (ToF-SIMS) showing the sputtering process that generates secondary ions. (Hao M, et al. 2021)
We can create a chemical map with a lateral resolution of 200 nm using ToF-SIMS imaging. 3D samples can also be reconstructed using ToF SIMS sputtering depth analysis to a depth of 1 m. The benefits of using our ToF SIMS analysis technology include but are not limited to:
- Qualitative analysis of molecular surface composition
- Ideal for chemical mapping of structures as small as 200 nm
- Depth profiles up to 1 µm can be generated
- 0.00x amu mass resolution; particles with the same nominal mass can be easily distinguished from each other.
- Mass range 0-10,000 amu; can detect ions, isotopes and molecular compounds
- Ideal for chemical mapping of structures as small as 200 nm
- Detection limit of trace elements in the ppm range
- Depth profiling capability; continuous sputtering of the surface allows analysis of the chemical formation on the surface of the material.
- Retrospective analysis; each pixel of the ToF-SIMS map represents a complete mass spectrum
- Suitable for many solid materials, such as metal, ceramic, glass or plastic
Reference
- Hao M, et al. (2021). "Characterization of polymeric surfaces and interfaces using time-of-flight secondary ion mass spectrometry." J Polym Sci. 1-25.
