The main objective of this thesis is to refine the methodology for the elemental quantification of high-energy photoemission spectra (HAXPES) in order to achieve uncertainty levels of 5 per cent or less in the measurements carried out, by incorporating, into the recently established methodology, material-dependent physical data relating to the inelastic energy losses of photoelectrons (REELS data). The quantification carried out using this protocol—refined through a study of pure elements—will be compared with existing methods to determine the gain in precision. Subsequently, it will be applied to binary, doped binary and ternary compounds of technological interest, for example for FD-SOI technology; in parallel, a calibration study will be carried out using measurements taken by a cleanroom spectrometer on the same samples; integration aspects will be investigated using measurements on test boxes. In particular, the aim will be to investigate the extent to which the composition measured by HAXPES on a material prepared prior to the transistor integration stages (for the optimisation of deposition processes) compares with that determined by other techniques (atomic probe tomography, TEM-EDX, TEM-EELS) at the end of the integration of nanometric devices.