Specific Process Knowledge/Characterization/XPS/XPS Chemical states: Difference between revisions
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=Chemical state= | =Chemical state= | ||
[[image:Si2p.JPG|600x600px|left|thumb|XPS Si2p spectrum of a Si reference sample (red curve), and a Si sample that was treated in HF shortly before the measurement was done (green curve). ]] | |||
The chemical properties of an element is determined by the outermost electronic shells. When a chemical bond between two atoms is formed there is an exchange of loosely bonded electrons between them. This exchange of valence electrons induces a small energy shift in all electronic shells of the atoms that may be detected by XPS. Hence, one can see if, for instance, silicon is in oxidation state 0 (Si-Si bond in bulk silicon), oxidation state +IV (Four Si-0 bonds in SiO<sub>2</sub>) | |||
For instance, both carbon and silicon have four valence electrons in their out | |||
Due to the so called chemical shift, it is possible to get information about the chemical state of the probed atoms. | Due to the so called chemical shift, it is possible to get information about the chemical state of the probed atoms. | ||
The core electrons of the atoms are affected, meaning that the binding energy of the electrons are slightly shifted, when an atom is bonded to atoms of other elements. | The core electrons of the atoms are affected, meaning that the binding energy of the electrons are slightly shifted, when an atom is bonded to atoms of other elements. | ||