Nb Josephson junction with a Hf/HfN double overlayer

An Nb Josephson junction with a Hf/HfN double overlayer structure was fabricated and presented. The characteristics of the device were not affected by annealing at temperatures up to 350 degrees celsius. The Hf layer acted as a layer for the tunneling barrier formation and as an effective etch stop for a reactive ion etching process during the fabrication of the junction. The HfN layer acted as a stop for grain boundary diffusion between the Nb and Hf layers.