Specific Process Knowledge/Characterization/Element analysis: Difference between revisions

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 [[image:SIMScascade.gif|200x200px|right|thumb|A beam of high energy ions is rastered on the surface of the sample. Some of the atoms that used to make up the surface are sputtered off and emitted as secondary ions. The mass of the these ions is measured with a mass spectrometer.]]
-When a solid sample is sputtered by primary ions of few keV energy, a fraction of the particles emitted from the target is ionized. Secondary Ion Mass Spectrometry consists of analyzing these secondary ions with a mass spectrometer. Secondary ion emission by a solid surface under ion bombardment supplies information about the elemental, isotopic and molecular composition of its uppermost atomic layers.
+In the Atomika SIMS the samples are bombarded with a beam of either oxygen or caesium ions. If accelerated to high energy and rastered across the sample
+these ions will be able to gradually sputter off the surface atoms in a small area. In this way one layer after another is peeled off the sample. Some of the surface atoms are emitted as ionized particles.
+These charged species are led through a mass spectrometer where a magnetic field is used to deflect them. The deflection increases with charge and decreases with mass and we are therefore able detect and count them according to their mass. This technique is called Secondary Ion Mass Spectrometry or SIMS.
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+The technique is highly sensitive and is therefore ideal if you want to check for a contamination. In a typical application one puts three samples into the SIMS.
 == Depth resolution using EDX ==