Abstract : This thesis presents a study of the deposition and structural as well as electrical properties of thin films of thermoelectric materials Mg2Sn-Mg2Si. Polycrystalline thin films of the Mg2Sn compound and of solid solutions Mg2Si1-xSnx were deposited on several types of substrate at room temperature, by co-sputtering assisted by microwave plasma. The influence of deposition parameters on structural and electrical properties of deposited films was studied. Thus, the chemical composition of thins films was fully controlled by the means of the independent polarization of targets of constituent elements. Phase composition and microstructure of deposited films were found depending on the deposition pressure, on the microwave power, on the geometry of the deposition chamber (target-substrate distance, configuration of the deposition chamber). These structural properties, in turn, have a strong impact on the electrical properties of the deposited films. Mg2Sn thin films doped with Ag, deposited under optimal condition, presented a power factor at room temperature comparable to conventional thermoelectric materials. A major advance of this study was to demonstrate the deposition of thin films of single phase solid solutions Mg2Si1-xSnx. Improvements are proposed to increase the electrical conductivity and thus the power factor of these films.