Title :
High quality Nb-based tunnel junctions for high frequency and digital applications
Author :
Dmitriev, Pavel N. ; Lapitskaya, Irina L. ; Filippenko, Liudmila V. ; Ermakov, Andrey B. ; Shitov, Sergey V. ; Prokopenko, Georgy V. ; Kovtonyuk, Sergey A. ; Koshelets, Valery P.
Author_Institution :
Inst. of Radio Eng. & Electron., Russian Acad. of Sci., Moscow, Russia
fDate :
6/1/2003 12:00:00 AM
Abstract :
A number of new fabrication techniques are developed and optimized in order to fit the requirements of contemporary superconducting electronics. To achieve ultimate performance of integrated submm receivers with operational frequency of 1 THz, tunnel junctions with AlN tunnel barrier having a RnS value as low as 1 Ωμm2 have been developed. High quality characteristics of Nb/AlN/Nb tunnel junctions with Rj/Rn=16 and RnS=10 Ωμm2 have been demonstrated. Electron Beam Lithography (EBL) in combination with Chemical Mechanical Polishing (CMP) has been incorporated to produce Nb/AlN/Nb junctions with 0.03 μm2 area. A new approach to obtain overdamped Nb/AlOx/Nb tunnel junctions has been proposed and realized. The dependencies of the main parameters of novel junctions on the current density and circuit geometry have been studied. These junctions may have a good potential in Josephson junction arrays and Single-Flux-Quantum applications (RSFQ).
Keywords :
Josephson effect; aluminium compounds; chemical mechanical polishing; digital integrated circuits; electron beam lithography; niobium; submillimetre wave mixers; submillimetre wave receivers; superconducting arrays; superconducting integrated circuits; superconducting microwave devices; superconductor-insulator-superconductor mixers; 1 THz; CMP; Josephson junction arrays; Nb-AlN-Nb; Nb-AlOx-Nb; Nb/AlN/Nb tunnel junctions; RSFQ applications; SIS tunnel junctions; chemical mechanical polishing; circuit geometry; currents density; digital applications; electron beam lithography; fabrication techniques; high frequency applications; high quality Nb-based tunnel junctions; integrated submm receivers; overdamped Nb/AlOx/Nb tunnel junction; single-flux-quantum applications; Chemicals; Circuits; Current density; Electron beams; Fabrication; Frequency; Geometry; Josephson junctions; Lithography; Niobium;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.813657
