Advanced Materials Characterization Chapter 6 Auger Electron Spectroscopy

Advanced Materials Characterization Chapter 6 - Igor Bello

Lise Meitner observed the Auger phenomenon while she studied beta-radiation. She published this phenomenon in the journal of Zeitschrift für Fyzik in 1922. Later Pierre Victor Auger observed this tertiary effect in the photoemission process. Auger was credited for his observation and the process was named after him. In 1953, Lander suggested using Auger electron signals for surface analysis.

The process that involves the transition of 3 electrons at different energy levels within an atom and emission of an electron from a shallower level is called Auger process. The emitted electron is named Auger electron. Auger process can be induced by both photon and electron interactions with solids. Thus, Auger electrons are also induced by x-rays in x-ray-photoelectron spectroscopy (XPS). These electrons can be used for calibration of energy scales in XPS spectra. Auger electrons induced by electron-solid interactions are particularly used at the chemical analyses of materials due to the high efficiency of electron stimulation.

Chemical analyses using electron beam probes give advantage over other techniques because electron beams can be focused to small spot sizes. At material analyses, the small spot size of the probe is the fundamental condition to attain a high spatial resolution. The second condition for high spatial resolution is the small escape depth (small escape volume) of Auger electrons, which indeed come from very surface regions. Thus, the spatial resolution of the Auger analysis is very high. This property enables us to do compositional analysis and mapping of chemical elements over material surfaces at spatial resolutions close to that of SEM (below 5 nm).