Electron Spectroscopy for Chemical Analysis (ESCA)

Electron Spectroscopy for Chemical Analysis (ESCA), also called X-ray Photoelectron Spectroscopy (XPS) is a surface chemical analysis technique. This technique is used to measure the elemental and chemical state information for concentrations above 0.1 to 1 Atomic% depending on the element in the outermost 20A-50 Å of a surface. All elements except H and He can be detected using this technique. In conjunction with an Ar+ ion beam, elemental and chemical composition can be characterized as a function of depth at a very high resolution. This capability is useful in characterizing interfaces. The advantages of ESCA 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. Small spot (up to 10 micron spot) capability is also useful in elemental and chemical state mapping of surfaces.