Strain engineering is now considered as one of the most important boosters of microelectronics among other technologies such as SOI (Silicon On Insulator) and high-κ metal gates. By applying a stress in the channel of MOSFET (Metal Oxyde Semiconductor Field Effect Transistor) devices, the charge carriers mobility can be significantly increased. Consequently, there is now a need for a strain metrology at the nanometer scale. Dark-field electron holography is a TEM (Transmission Electron Microscopy) technique invented in 2008 that allows to map strain with micrometer field-of-view and nanometer spatial resolution. In this thesis, the technique was developed on the CEA Titan microscope. First, different developements were carried out concerning the sample preparation, the illumination/acquisition conditions and the reconstruction of the holograms. The sensitivity and the accuracy of the technique were evaluated through the characterization of Si_{1-x}Ge_{x} layers epitaxied on Si and by comparing the results with mechanical finite element simulations. Then, the technique was applied to the study of annealed SiGe(C)/Si superlattices that are used in the construction of new 3D architectures such as multichannel or multiwires transistors. The influence of the different relaxation mechanisms on the strain especially Ge interdiffusion and β-SiC clusters formation was investigated. Finally, dark-field electron holography was applied to the characterization of uniaxially strained pMOS transistors by SiN liners and recessed SiGe sources and drains. The measurements allowed to confirm the strain additivity of the two processes.