The principle of the Low energy Electron induced X-ray Emission Spectrometry (LEXES) consists of irradiating a solid sample by a low energy electron beam and analyzing the soft X-rays emitted by the target. Because the X-rays are characteristic of the emitting elements, selective elemental analysis is achieved. The analyzed depth can be varied between 1 to 500 nanometers, depending on the parameters: element, matrix and primary electron energy.   The precise modeling of primary electron/matter interaction and of the absorption of the emitted soft X-rays allows the PRECISE ELEMENTAL QUANTITATION of the sampled depth over a wide range of concentration (from 100 at% down to tens ppm). The matrix effects are small and well modeled. Hence, standard sample are readily available (pure materials or stochiometric compounds). Another strong point of the technique is its NON-DESTRUCTIVE nature.

One major application of the LEXES technique to the semiconductors is the fast and quantitative dose measurement of ultra-shallow implants over a wide range of dose, with or without annealing. The technique provides sensitivity matching perfectly the needs of LE and ULE (Ultra Low Energy) implantation technology. As the technique is based on electron beam technology, the analyzed area can be compatible with pattern analysis for product wafer analysis.
Other crucial today applications are the elemental quantitation of nitrogen and oxygen in oxinitrides, and or boron, carbon and germanium quantitation in SiGe technology.
In addition to its dose measurement capability, a depth distribution information can be extracted from the analysis of signal at different primary energies (different sampled depths). 

The increasing needs for accurate dose measurement of ULE implants and the acknowledged expertise of CAMECA in SIMS and EPMA technology has led to the development of a new instrument based on LEXES technique, the CAMECA Shallow Probe. This Fab-line metrology tool provides fast, quantitative and non-destuctive Element composition AND thickness measurement of full 200 and 300mm wafers, allowing uniformity control of Ultra Thin layers on full patterned or unpatterned wafers. It complies with semiconductor manufacturing environment standards (SEMI, SECS-GEM) .