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 NbCxN1-x,/TiNx/NbCxN1-xSNS junctions using TiNxas the barrier material. Structural studies show that TiNxfilms 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 TiNxfilms range from 4SμΩ·cm to 1lOμΩ·cm, depending on the values of N2partial pressure. Polycrystalline NbCxNfilms with high Tchave been grown on TiNxfilms by rf sputtering. NbCN1-x/TiNx/NbCxNl-xtrilayer junctions with various dimensions and TiNxthicknesses have been fabricated. Current-voltage characteristics of the junction with a 130nm-thick TINxbarrier show nonhysteiretic behavior and strong critical current modulatilon with applied magnetic field, suggesting the characteristics of a Josephson SNS large junction. The IcRNproduct and the critical current density Jcof a 5μm x 5μm junction at 4.2K are estimated to be 30μV and 36kA/cm2, respectively.