Sub /spl mu/m Nb/AlO/sub x//Nb Josephson junctions fabricated by anodization techniques

Technological processes for the fabrication of Nb/AlO/sub x//Nb Josephson junctions with areas as small as 0.04 /spl mu/m/sup 2/, based on anodization techniques, are investigated. A cross strip process requiring only two masks is compared with a standard three mask etching and anodization process. Details of the fabrication processes as well as the electrical characterization at 4.2 K and 30 mK of tunnel junctions fabricated by the different methods are presented. Limitations and applications of the two different processes are discussed.