Character and fabrication of Al/Al2O3/Al tunnel junctions for qubit application

• DOI: 10.1007/s11434-011-4821-4
• Publication Date: 2012-01-21T04:49:54Z
• Authors: DanDan Shen; Ran Zhu; WeiWei Xu; JunJie Chang; ZhengMing Ji; GuoZhu Sun; ChunHai Cao; Jian Chen
• Keywords: Tunnel junction; Oxidizing agent; Superconducting tunnel junction; Leakage (economics)

The superconductive Josephson junction is the key device for superconducting quantum computation. We have fabricated Al/ Al2O3/Al tunnel junctions using a double angle evaporation method based on a suspended shadow mask. The Al2O3 junction barrier has been formed by introducing pure oxygen into the chamber during the fabrication process. We have adjusted exposure conditions by changing either the oxygen pressure or the oxidizing time during the formation of tunnel barriers to control the critical current density Jc and the junction specific resistance Rc . Measurements of the leakage in Al/Al2O3/Al tunnel junctions show that the devices are suitable for qubit applications.