Fabrication and dc characteristics of vertically stacked sis-type structures for use as low-temperature detectors

We discuss the fabrication and current-voltage characteristics (ivc) of Sn-(l-Sn)₅ and Nb-AI-AIO-Nb)₁₂ multilayer devices consisting of tunnel junctions stacked on top of one another. Three-terminal devices including a phonon and quasiparticle generator and both a single-junction (sj) and multijunction (MJ) detector based on tin structures have been fabricated, The mj detector showed better sensitivity to the same phonon irradiation-level compared with the sj detector. The result shows that the multijunction approach to low-temperature detector design is promising and might improve the energy resolution and sensitivity of detectors. For niobium-based structures, we have successfully employed a timed ion milling to define the area of devices.