串联超导量子干涉器件阵列制备与测试分析  

Fabrication and experimental analysis of series superconducting quantum inteference device array

作　　者：梁恬恬 张国峰[1,2] 伍文涛 倪志 王永良[1,2] 应利良[1,2] 伍俊[1,2] 荣亮亮 彭炜[1,2,3] 高波 Liang Tian-Tian;Zhang Guo-Feng;Wu Wen-Tao;Ni Zhi;Wang Yong-Liang;Ying Li-Liang;Wu Jun;Rong Liang-Liang;Peng Wei;Gao Bo(State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;Center for Excellence in Superconducting Electronics,Chinese Academy of Sciences,Shanghai 200050,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海微系统与信息技术研究所,信息功能材料国家重点实验室,上海200050 [2]中国科学院超导电子学卓越创新中心,上海200050 [3]中国科学院大学,北京100049

出　　处：《物理学报》2021年第17期299-304,共6页Acta Physica Sinica

基　　金：上海市自然科学基金(批准号:18ZR1447400)资助的课题.

摘　　要：串联超导量子干涉器件(superconducting quantum interference device,SQUID)阵列通过增加SQUID数量来达到提升信噪比的目的,即SQUID电压信号随SQUID数目比例增加而总电压噪声正比于SQUID数目的平方根值.本文介绍了利用自主工艺线进行串联SQUID阵列研究的相关研究进展,实现了SQUID数量分别为200和800的阵列集成,测试得到磁通噪声达到0.5μФ_(0)/√Hz和输入电流灵敏度35μA/Ф_(0),等效输入电流噪声达到18pA/√Hz.另外,还给出了阵列参数与集成SQUID数量的关系,验证了设计可靠性和工艺一致性.Superconducting quantum interference device(SQUID)has been used as an extremely sensitive flux sensor up to now.Series SQUID array(SSA)is made up of several identical element-SQUIDs in series,in which each element-SQUID is coupled with the same set of input coils by mutual inductance to realize the amplified output of the input current.From the noise viewpoint,each element-SQUID in SSA is independent of each other,resulting in the total voltage noise across the array rising linearly with the square root of the number of element-SQUIDs.From the perspective of input signals,since the signals come from the same set of input coils,the voltage output of the array is enlarged with the proportion of element-SQUID number,N.Taken together,the signal-to-noise ratio of SSA is increased by√N times,or the flux noise of SSA is reduced by 1/√N times compared with that of an element-SQUID ideally.However,with the increase in the number of element-SQUIDs in series,the chip design of SSA becomes more complicated,which puts forward higher requirements for the consistency and stability of its fabrication process.Besides,there exists a certain flux coherence between element-SQUIDs in SSA,whose normal operation depends on the working state of each element-SQUID in the array.In this paper,the fabrication of series SQUID array is carried on the autonomous superconducting micro-nano process platform,with a yield rate reaching over 80%on a 4-inch standard silicon wafer.Two kinds of SSAs with 200 and 800 element-SQUIDs,respectively,are integrated in a meandering way on a chip in a millimeter area.Home-made directly-coupled readout circuit is used to obtain the characteristics of SSA.The experimental results reveal that the flux noise at best working point is as low as 0.5μФ_(0)/√Hz and the current sensitivity is about 35μA/Ф_(0),thus,the equivalent input current noise is achieved at a level of 18 pA/√Hz.Additionally,the dependence of relevant parameters in array on the number of element-SQUIDs is verified,which is consistent wi

关 键 词：超导量子干涉器件 磁通噪声 超导制备工艺 

分 类 号：O413[理学—理论物理]