%0 Journal Article
%T Processing and characterization of high Jc NbN superconducting tunnel junctions for THz analog circuits and RSFQ
%A Larrey, V.
%A Villegier, J-C
%A Salez, M.
%A Miletto-Granozio, F.
%A Karpov, A.
%J IEEE Trans. Appl. Supercond.
%D 1999
%V 9
%N 2
%F Larrey_etal1999
%O exported from refbase (https://db.rplab.ru/refbase/show.php?record=1081), last updated on Fri, 03 Jun 2016 09:17:16 -0500
%X A generic NbN Superconducting Tunnel Junctions (STJ) technology has been developed using conventional substrates (Si and SOI-SIMOX) for making THz spectrometers including SIS receivers and RSFQ logic gates. NbN/MgO/NbN junctions with area of 1 /spl mu/m/sup 2/, Jc of 10 kA/cm/sup 2/ and low sub-gap leakage current (Vm>25 mV) are currently obtained from room temperature sputtered multilayers followed by a post-annealing at 250/spl deg/C. Using a thin MgO buffer layer deposited underneath the NbN electrodes, ensures lower NbN surface resistance values (Rs=7 /spl mu//spl Omega/) at 10 GHz and 4 K. Epitaxial NbN [100] films on MgO [100] with high gap frequency (1.4 THz) have also been achieved under the same deposition conditions at room temperature. The NbN SIS has shown good I-V photon induced steps when LO pumped at 300 GHz. We have developed an 8 levels Al/NbN multilayer process for making 1.5 THz SIS mixers (including Al antennas) on Si membranes patterned in SOI-SIMOX. Using the planarization techniques developed at the Si-MOS CEA-LETI Facility, we have also demonstrated on the possibility of extending our NbN technology to high level RSFQ circuit integration with 0.5 /spl mu/m/sup 2/ junction area, made on large area substrates (up to 8 inches).
%K RSFQ
%K NbN
%K SIS
%R 10.1109/77.783713
%U https://doi.org/10.1109/77.783713
%P 3216-3219