On the other hand, TOF-SIMS is a technique that can detect elemental and molecular information existing on the outermost surface of a sample with a low primary ion beam dose (1×1012 atoms/cm2 or less). It is also called static SIMS because there is so little sputtering (<0.1% of a monolayer) during data acquisition that the surface is “static”. Virtually no sputtering takes place. The primary ion beam is a pulsed. The technique can be used to obtain molecular information on the outermost surface of the sample.
TOF-SIMS typically uses heavy ions (Bi, Au, Ga.) suitable for detection of molecular information on the surface, These species can be made easily into finely-focused ion beams which can be used to obtain high spatial-resolution ion images. This is an effective technique for identifying organic substances remaining on the surface. An auxiliary sputter source can also be mounted on the TOF-SIMS device so that secondary ions can be obtained from deeper into the material instead of being limited to just the sample surface. In that case, the detection sensitivity of elemental species is inferior to that of magnetic-sector SIMS or quadrupole SIMS instruments, but in-depth analysis is still possible.