Fabrication of Al/AlO sub(x)/Al Josephson junctions and superconducting quantum circuits by shadow evaporation and a dynamic oxidation process

• Published in: Chinese physics B 2013-06, Vol.22 (6), p.060309-1-060309-5
• Main Authors: Wu, Yu-Lin, Deng, Hui, Yu, Hai-Feng, Xue, Guang-Ming, Tian, Ye, Li, Jie, Chen, Ying-Fei, Zhao, Shi-Ping, Zheng, Dong-Ning
• Format: Article
• Language: English
• Subjects: Aluminum; Circuits; Dynamics; Evaporation; Flux; Josephson junctions; Qubits (quantum computing); Shadows; Superconductivity
• ISSN: 1674-1056; 1741-4199
• DOI: 10.1088/1674-1056/22/6/060309

Besides serving as promising candidates for realizing quantum computing, superconducting quantum circuits are one of a few macroscopic physical systems in which fundamental quantum phenomena can be directly demonstrated and tested, giving rise to a vast field of intensive research work both theoretically and experimentally. In this paper we report our work on the fabrication of superconducting quantum circuits, starting from its building blocks: Al/AlO sub(x)/Al Josephson junctions. By using electron beam lithography patterning and shadow evaporation, we have fabricated aluminum Josephson junctions with a controllable critical current density (j sub(c)) and wide range of junction sizes from 0.01 mu m super(2) up to 1 mu m super(2). We have carried out systematical studies on the oxidation process in fabricating Al/AlOx/Al Josephson junctions suitable for superconducting flux qubits. Furthermore, we have also fabricated superconducting quantum circuits such as superconducting flux qubits and charge-flux qubits.