Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a surface analytical technique that focuses a pulsed beam of primary ions onto a sample surface, producing secondary ions in a sputtering process. Analyzing these secondary ions provides information about the molecular and elemental species present on the surface. For example, if there were organic contaminants, such as oils adsorbed on the surface, TOF-SIMS would reveal this information, whereas other techniques may not. Since TOF-SIMS is a survey technique, all the elements in the periodic table, including H, are detected. Moreover, TOF-SIMS can provide mass spectral information; image information in the XY dimension across a sample; and also depth profile information on the Z dimension into a sample.

The surface sensitivity of TOF-SIMS makes it a good first pass at problem solving. Once you have an idea of what you are dealing with, you can then use other techniques to obtain additional information.

Evans Analytical Group® (EAG) has been doing TOF-SIMS commercially longer than any other company; our expertise is second to none. This is particularly crucial for TOF-SIMS, where the data sets can be extremely complex and may require more interpretation or data processing than other analytical techniques. The imaging capabilities of TOF-SIMS can provide elemental and molecular information from defects and particles on the micron scale. TOF-SIMS can also be used for depth profiling and compliments dynamic SIMS. The advantages for TOF-SIMS for profiling are its small areas capabilities and also its ability to do survey depth profiles.

At EAG, we use TOF-SIMS to assist customers with quality control, failure analysis, troubleshooting, process monitoring, and research and development. For example, the information we provide when investigating wafer surface contamination issues can help determine the specific source of the problem, such as pump oils or component outgassing, or it may indicate problems with the wafer-processing step itself (e.g. etch residue). We also make sure you have person-to-person service throughout the process, so that you understand the test results and their implications.

View Application Notes

Ideal Uses for TOF-SIMS Analysis		Relevant Industries for TOF-SIMS Analysis
Surface microanalysis of organic and inorganic materials Mass spectra direct from surfaces Ion imaging of surfaces		Aerospace Automotive Biomedical/biotechnology Compound Semiconductor Data Storage Defense Displays Electronics Industrial Products Lighting Pharmaceutical  Photonics Polymer Semiconductor Solar Photovoltaics Telecommunications
Strengths of TOF-SIMS Analysis		Limitations of TOF-SIMS Analysis
Specific molecular information on thin (sub-monolayer) organic films/contaminants Surface analysis that allows more complete characterization of a surface Excellent detection limits (ppm) for most elements Quantitative element analysis of Si and GaAs Probe size ~0.2 µm for imaging Insulator and conductor analysis  Non-destructive Depth profiling is possible Whole wafers up to 200 mm		Usually not quantitative without standards Samples must be vacuum compatible It can be too surface sensitive: Sample packaging and prior handling may impact quality of results Analysis order is important, surface-damaging tests should be done after TOF-SIMS Very surface specific—only examines top couple of monolayers

Application Notes