X-Ray Photoelectron spectroscopy
X-ray Photoelectron Spectroscopy/Electron Spectroscopy for Chemical Analysis
X-ray Photoelectron Spectroscopy (XPS), also called Electron Spectroscopy for Chemical Analysis (ESCA) is a surface chemical analysis technique. This technique is used to measure the elements and chemical states of materials for concentrations above 0.1 to 1 Atomic % depending on the element. XPS uses an X-ray beam to irradiate the sample and thus is an extremely surface sensitive analysis measuring the outermost 20-50 Å of a surface. Once ejected the quantity and energy of electrons is measured. In conjunction with an Ar+ ion beam, elemental and chemical composition can also be characterized as a function of depth. All elements except H and He can be detected using this technique. This capability is useful in characterizing interfaces. The advantages of XPS is its ability to analyze non-conducting materials, such as ceramics and plastics, with minimum charging effects and the ability to relate small shifts in the peak positions to differences in the chemical state. Common applications for XPS are determining thin film composition for process development or process control, analyzing for surface contamination on failing materials or verifying surfaces are free of residual materials.
- Physical Electronics Quantum 2000