自对准法制备Nb/AlO_x/Nb超导Josephson结及其直流特性测试  

Self-aligning fabrication and DC characterization of Nb/AlO_x/Nb superconducting Josephson junctions

作　　者：赵娜[1] 刘建设[1] 李铁夫[1] 吴威[1] 赵虎[1] 陈炜[1] 

机构地区：[1]清华大学微电子学研究所,清华信息科学与技术国家实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2012年第11期1555-1558,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金重点项目(60836001);国家"九七三"重点基础研究发展计划(2011CBA00304)

摘　　要：超导量子比特系统是实现大规模量子计算的可行方案之一。该文采用集成电路平面工艺制备了基于Nb/AlOx/Nb 3层膜结构的超导Josephson结,为制备性能可靠的超导量子比特提供了一定基础。工艺中采用了自对准技术形成结区,从而有效地保护器件结构并降低了工艺复杂度。搭建了超导Josephson结直流特性低温测试系统,并对制备的Josephson结进行了直流特性测试,得到Josephson结在不同温度下的伏安特性,并观察到铌(Nb)的超导能隙电压2.85mV的跳变。同时,测量得到Josephson结临界电流随温度变化的关系,与Ambegaokar和Baratoff的理论结果相符合。Superconducting qubit systems are one way to implement large-scale quantum computations. Nb/AlOx/Nb superconducting Josephson junctions were fabricated using a planar process as the groundwork for fabricating reliable qubits. The junction area was formed by a self-aligning technology, which effectively protected the device and reduced the fabrication complexity. A low temperature system was constructed to characterize the Josephson junctions with automatic generation and acquisition of signals. The I-V characteristics of the Josephson junctions were measured at different temperatures with an observed jump at the niobium superconducting gap voltage of 2.85 inV. The critical currents of the Josephson junctions were measured at different temperatures, which agree well with the theoretical result of Ambegaokar and Baratoff.

关 键 词：超导 JOSEPHSON结 自对准 直流特性测试 伏安特性 临界电流 

分 类 号：O511.9[理学—低温物理] TN4[理学—物理]