Fabrication and electrical characterization of Nb/TaNx/Nb Josephson junctions is reported. At the thickness of TaNx layer of about 10 nm, the junctions are self-shunted and display the critical current density, jc, above 100 kA/cm2, and the critical voltage, Vc, of about 0.59 mV at 4.2 K. The critical voltage is defined as Vc=IcRq, where Ic is the Josephson critical current and Rq is the resistance of the quasiparticle branch of the current-voltage characteristic (IVC) at the level of maximum Ic. The value of Rq may be different from the junction’s normal state resistance, Rn, and from the resistance obtained by a linear fit of the resistive subgap portion of the IVC. It is suggested that the junctions are promising for applications in superconducting electronics including single-flux quantum digital and quantum computing circuits.

The author received support from the NSF DISCoVER Expedition award under grant no. CCF- 2124453. The author acknowledges the use of facilities of the Materials Research Center at Northwestern University, supervised by J. B. Ketterson and supported by NSF.