Jonctions SIS en Nb/Al2O3/Nb pour des récepteurs en radioastronomie millimétrique et submillimétrique

To prepare radioastronomical missions on satellites, a balloon-borne experiment called PRONAOS-SMH is being developped under the responsability of the Centre National d'Etudes Spatiales. The 380 GHz SIS receiver is entirely prepared in our laboratory. The description of this project is made in the introduction. The first part explains the bases of the superconductivity, the Josephson effect and the SIS mixers. These concepts are very usefull to understand how the whole SIS receiver works. Then, the machines used for the junctions fabrications are described in a second part: the basic principles of evaporation, sputtering, etching and opticallithography are explained. A process of trilayer deposition to obtain small Nb/Al-AIOx/Nb SIS junctions (1 micron square) with excellent I/V characteristics, good reliability and high current densities is explained in the third part. To optimize this process, it has been usefull to develop several studies which are exposed here. The integration of these junctions in millimeter and submillimeter receivers is described in the part IV. The first results obtained with the 380 GHz receiver are promising : DSB receiver noise is 310K at 374GHz.