Preparation of NbC/sub x/N/sub 1-x/ Josephson junctions with TiN/sub x/ barriers

This paper presents the preparation process and the characteristics of titanium nitride films and nonhysteretic NbC_xN_1-x,/TiN_x/NbC_xN_1-x SNS junctions using TiN_x as the barrier material. Structural studies show that TiN_x films prepared by rf sputtering at room temperature have a preferential orientation of TiN(111) phase, while those grown at higher substrate temperatures are (200)-oriented. Resistivilies of the TiN_x films range from 4SμΩ·cm to 1lOμΩ·cm, depending on the values of N₂ partial pressure. Polycrystalline NbC_xN films with high T_c have been grown on TiN_x films by rf sputtering. NbC_{N1-x/TiNx/NbCxNl-x trilayer junctions with various dimensions and TiNx thicknesses have been fabricated. Current-voltage characteristics of the junction with a 130nm-thick TINx barrier show nonhysteiretic behavior and strong critical current modulatilon with applied magnetic field, suggesting the characteristics of a Josephson SNS large junction. The IcRN product and the critical current density Jc of a 5μm x 5μm junction at 4.2K are estimated to be 30μV and 36kA/cm², respectively.}