Due to the need to produce high-quality industrial components for different parts of electronics, electrical, and other machines, manufacturers seek particular characteristics and features of the materials used in these processes. Using a reliable surface analysis technique is vital for quality analytical results. ToF-SIMS, also known as Time-of-Flight Secondary Ion Mass Spectrometry, is a reliable technique used for surface analysis.
ToF-SIMS is a surface analysis method for the chemical characterization of solid surfaces in the laboratory. The ToF-SIMS technique involves surface bombardment with a finely focused beam of charged ions of up to 30-kilo electronvolts (keV) energy from an ion gun. The bombardment of the material surface with the primary charged particles leads to the ejection of secondary ions from the solid surface under analysis.
Chemical Screening using ToF-SIMS
The sample is bombarded with a primary ion beam such as Bi+ resulting in the sputtering or desorption of secondary ions from the top 1-3 topmost monolayers of the material sample. The mass spectrometer detects the secondary ions ejected from the sample material surface and provides data on the mass of the specimen.
In the ToF-SIMS mass spectrometry analysis, the secondary ion mass-to-charge ratio is determined by a time of flight measurement of ions.
The ToF-SIMS analysis technique identifies the atomic, elemental, and molecular species in the to 1 – 3 monolayers of a sample. The method is appropriate for analyzing conductive and insulating surfaces and helps identify compounds and characterize complex mixtures. The ToF-SIMS analysis technique has high sensitivity and can detect even tiny amounts of substances in the part-per-million(ppm).
ToF-SIMS analysis can resolve chemical composition in 2D and attain a lateral solution with a resolution of 200 nm or even higher.
ToF-SIMS is suitable for compositional depth analysis of both inorganic materials and organic materials. ToF-SIMS technique enables complete mass spectrum with a single beam bombardment of primary ions.
Wrap your sample with aluminum foil or use a clean filter paper to prevent unwanted surface contamination during handling and transportation.
If organic contamination occurs, it’s still possible to do ToF-SIMS analysis after appropriate cleaning of the sample in the laboratory.
In the past, experts used chemical cleaning to clean surfaces, which involves chemical rinsing and mechanical cleaning to clean contaminated surfaces. However, these methods pose a risk of new contamination.
Mechanical cleaning involves scratching the surface and cutting; however, it is time-consuming and subject to new contamination. Also, the method is not suitable for semi-conductors due to their structure. Instead, industry experts prefer in-situ cleaning is over the other methods.
In-Situ cleaning by Ar Cluster ions
In-Situ cleaning by Ar Cluster ions provides a fast, efficient, and gentle method of removing molecular surface contamination. Applying suitable bombardment conditions helps selectively remove molecular contamination layers with thickness ranging from few nm to many µm without affecting the inner molecular structure.
The preparation of samples for ToF-SIMS analysis requires minimal preparation. In most cases, ToF-SIMS analysis takes place without any pre-treatment. However, the analysis sample has to be a vacuum-compatible material.
- ToF-SIMS Analyzable Materials
- Drying liquid residues
- Applications of ToF-SIMS Examples
- To analyze the surface composition of polymers previously pre-treated by etching.
- To determine the nature of reactions at the interface between a primer and an adhesive.
- To determine the surface chemical composition of sugarcane megass.
ToF-SIMS is a sensitive analysis method that will give accurate spectral and imaging information about surfaces of materials. The technique provides an in-depth understanding of the effects of processing conditions on surfaces of materials. ToF-SIMS analysis finds its application in almost all sectors of the economy, including medicine. Cleaning of surfaces of samples using the in-situ cleaning method proves to be efficient and reliable.