AES ( Auger Electron Spectroscopy)
Named after the French physicist Pierre Auger, this is the method with the highest spatial resolution (about 10nm). Similar to a scanning electron microscope (SEM), the sample is irradiated with an electron beam. The released electrons are analyzed for their energy, which in turn is characteristic of the respective element. In contrast to the EDX analysis of a SEM, AES provides the very near-surface (about 5 nm) composition of the sample. The method is well quantifiable and therefore can deliver concentrations.
All three methods described above can also measure the depth profiles of layer systems with nanometer resolution by means of alternating sputter removal and analysis.