PHYSICAL FOUNDATION OF QUANTITATIVE AUGER ANALYSIS

The possibility of using both an Auger peak height in the dN(E)/dE spectrum and an integrated N(E) spectrum as a measure of the Auger current is discussed and necessary relations are presented. The methods of the background determination are reviewed and discussed. The relation between the Auger current and the atomic concentration of a corresponding sample component is derived and the state of art in the field of theoretical and experimental determination of factors appearing in this relation (ionization cross-section, Auger transition probability, backscattering factor, and inelastic mean free path of Auger electrons) is presented. Approaches to the quantitative Auger analysis (QAA) of homogeneous, isotropic samples, including corrections for matrix factors, are presented and discussed. Problems arising when heterogeneous samples are analyzed are discussed and practical approaches to such an analysis are presented. The role of crystalline effects (the dependence of the Auger signal from crystalline samples on the direction of the primary electron beam and angular distribution of Auger electron emission from such samples) in QAA is discussed and examples of such crystalline effects are presented together with their physical foundation. Some rules are suggested allowing the quantitative Auger analysis to be performed with the smallest possible error.