NbN Josephson Junctions for Single-Flux-Quantum Circuits

作者：Akaike Hiroyuki^*; Naito Naoto; Nagai Yuki; Fujimaki Akira

来源：IEICE - Transactions on Electronics, 2011, E94C(3): 301-306.

DOI：10.1587/transele.E94.C.301

• NbN
• Josephson junctions
• self-shunted
• AlNx
• radical-nitridation

We describe the fabrication processes and electrical characteristics of two types of NbN junctions. One is a self-shunted NbN/NbNx/AlN/NbN Josephson junction, which is expected to improve the density of integrated circuits; the other is an underdamped NbN/AlNx/NbN tunnel junction with radical-nitride AlNx barriers, which has highly controllable junction characteristics. In the former, the junction characteristics were changed from underdamped to overdamped by varying the thickness of the NbNx layer. Overdamped junctions with a 6-nm-thick NbNx film exhibited a characteristic voltage of V-c = 0.8 mV and a critical current density of J(c) = 22 A/cm(2) at 4.2 K. In the

• 出版日期2011-3