Fabrication of NbTiN Josephson Junctions With Thermally Oxidized Hf Tunnel Barriers

We fabricated NbTiN Josephson junctions (JJs) with HfOx barriers on thermally oxidized Si substrates. Hf overlayers with different resistivities were used for the HfOx barrier formation. The Hf overlayer with low resistivity produced junctions with high quality parameters. The critical current density (Jc) was obtained in the range of 0.01-0.4 kA/cm2 by changing the thermal oxidation conditions of...