A. Matsumura et al., EFFECT OF AI OVERLAYER THICKNESS ON THE LEAKAGE CURRENT OF RADIATION DETECTORS USING NB AL-ALOX/NB SUPERCONDUCTING TUNNEL-JUNCTIONS/, Journal of applied physics, 76(8), 1994, pp. 4761-4765
Nb/Al-AlOx/Nb superconducting tunnel junctions for the application of
radiation detectors were fabricated using dc magnetron sputtering. The
surface morphology of polycrystalline Nb films was observed using an
atomic force microscope. Junctions with various Al film thicknesses we
re fabricated. The leakage current of the junctions is found to decrea
se as the Al thickness increases, indicating an improvement of the Al
film coverage over the Nb surface. X rays were detected with the junct
ions prepared and the low leakage property across the junction makes p
ossible x-ray detection with various size junctions up to 200 x 200 mu
m2.