Fabrication of high-quality submicron Nb/Al-AlO_x/Nb tunnel junctions  

作　　者：于海峰 曹文会 朱晓波 杨海方 于洪伟 任育峰 顾长志 陈赓华 赵士平 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences

出　　处：《Chinese Physics B》2008年第8期3083-3086,共4页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos 10474129 and 10534060);the Ministry of Science and Technology of China (Grant Nos 2006CB601007 and 2006CB921107)

摘　　要：Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and superconducting qubit applications of the Josephson devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions. The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm^2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature dependence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and superconducting qubit applications of the Josephson devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions. The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm^2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature dependence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.

关 键 词：Nb junctions FABRICATION superconducting qubit macroscopic quantum phenomena 

分 类 号：O511.4[理学—低温物理]