{"id":682,"date":"2026-06-16T13:20:04","date_gmt":"2026-06-16T04:20:04","guid":{"rendered":"https:\/\/www.ulvac-phi.com\/surface-analysis\/tof-sims\/"},"modified":"2026-07-09T15:23:41","modified_gmt":"2026-07-09T06:23:41","slug":"tof-sims","status":"publish","type":"page","link":"https:\/\/www.ulvac-phi.com\/en\/surface-analysis\/tof-sims\/","title":{"rendered":"What is TOF-SIMS?"},"content":{"rendered":"\n
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What is TOF-SIMS?<\/h2>\n <\/div>\n\n
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Principle<\/h3>\n

Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a technique in which an ion beam (primary ion) is irradiated on a solid sample and mass separation of the ions emitted from the surface (secondary ions) is performed using the difference in time-of-flight (time-of-flight is proportional to the square root of the weight).TOF-SIMS can obtain information regarding elements or molecular species within 1 nm of the sample surface at a very high detection sensitivity.The number of primary ions per unit area irradiated on the surface is small, at around 1012<\/sup> ions\/cm2 or less (number of atoms on the surface of a silicon sample is 1015<\/sup> atoms\/cm2<\/sup>), allowing for near-nondestructive analysis.<\/p>\n

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\n \"Schematic\n <\/div>\n <\/div>\n\n

Excitation source (primary ion gun)<\/h3>\n

In TOF-SIMS, a Liquid Metal Ion Gun (LMIG), which has a submicron-level probe diameter and can achieve pulses of a few hundred picoseconds, is widely used as the primary ion source. With LMIG, there are 3 types of ion sources to choose from, Ga, Au, and Bi. Ga ion beams are all monomers, while Au and Bi ion beams include many polymer ions. High-mass molecules can be analyzed efficiently by using polymer ions. Ga ions are suitable for analysis of low-mass areas (mainly elements) and Au and Bi ions are suitable for high-mass areas (mainly molecules).<\/p>\n\n

Charge compensation mechanism (low-energy electrons)<\/h3>\n

TOF-SIMS can measure either conductive or insulating materials, and it does not matter whether the sample is in the form of a powder, fiber, etc., as long as it can be introduced to a vacuum. When measuring insulating materials, primary ion and pulsed low-energy electrons are irradiated simultaneously to prevent charge build up on the sample due to primary ion irradiation.<\/p>\n\n

Secondary ion detection system (TRIFT\u2122 analyzer)<\/h3>\n
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Secondary ions emitted from a solid surface have energy distributions from several eVs to several dozen eVs, and a wide emission angle, which leads to differences in arrival time at a detector even if their masses are the same. TRIFT analyzers correct for the difference in time-of-flight caused by differences in energy, by letting high energy ions go outside the orbit. Additionally, secondary energy can be captured over a wide angle, enabling images with less shadow even with unevenness measuring several 100 \u00b5m.<\/p>\n <\/div>\n

\n \"TOF-SIMS\n <\/div>\n <\/div>\n
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