Abstract:
The main parameters of the tunneling barrier of the Josephson junctions Nb/AlO$_{x}$/Nb and Nb/AlN/Nb were estimated using the Simmons method in a wide range of current densities. The dependences of the height and width of the tunnel barrier on the resistivity for each type of junctions are experimentally determined. A decrease in the height of the AlN tunnel barrier by 0.3 eV, compared with the oxide one, makes it possible to obtain junctions with a current density above 15 kA/cm$^{2}$ at a technologically achievable insulation layer of the order of 10 Angstroms, which makes it possible to realize the quality parameter $R_{j}/R_{n}$ not lower than 25.
This work was supported by the Russian Scientific Foundation, project no. 19-19-00618. The tunnel junctions were fabricated at the V. Kotel’nikov Institute of Radio Engineering and Electronics of the Russian Academy of Sciences, the state task using UNU 352529.
Citation:
M. E. Paramonov, L. V. Filippenko, P. N. Dmitriev, M. Yu. Fominskii, A. B. Ermakov, V. P. Koshelets, “Parameters of the tunneling barrier of niobium – based superconducting structures”, Fizika Tverdogo Tela, 62:9 (2020), 1370–1374; Phys. Solid State, 62:9 (2020), 1534–1538