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High-functional Superconducting Tunnel Junction fabricated by Electron Beam Excited Plasma Ion Plating Method

电子束激发等离子体离子镀法制备高性能超导隧道结

基本信息

批准号：
12650316
负责人：
MOROHASHI Shin'ichi
金额：
$ 1.98万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650316/
关键词：
Superconducting Tunnel Junction High-vacuum EB Evaporation Facing Targets Sputtering X-ray Detector Photon Detector 超伝導Nb薄膜 AlOxトンネルバリア SiO_2層間絶縁膜

项目摘要

It is important to raise the tunneling efficiency of quasiparticles generated by incident X-ray or photon for the operation of superconducting tunneling junction as the detector. Using the electron beam evaporation technique under the high-vacuum pressure of 4 x 10^<-9>Pa, we fabricate epitaxial Nb and Ta layers on a sapphire substrate at the substrate temperature of 500 〜 700℃. Nb layer indicates the transition temperature (Tc) of 〜 9.3 K and the residual resistance ratio (RRR) of 〜 50. Ta layers indicates Tc 〜 4.5 K and RRR of 45 〜 140.We have fabricated a Nb/AlOx-Al/Nb Josephson junction using magnetron-facing target sputtering technique. Nb and Al layers can be deposited under the high-density plasma in the condition that it is not directly exposed to the plasma region generated between a pair of targets. The transition temperature of the Nb layer and the residual resistance ratio have indicated 9.3 K and more than 3. The Nb/AlOx-Al/Nb Josephson junction has exhibited current-voltage characteristics with a low subgap leakage current.

提高入射X射线或光子产生的准粒子的隧穿效率对超导隧道结作为探测器的工作具有重要意义。采用电子束蒸发技术，在4 × 10 ~（-3）Pa的高真空环境<-9>下，在500 ~ 700℃的衬底温度下，在蓝宝石衬底上制备了Nb和Ta外延层。Nb层表明转变温度（Tc）为109.3 K，剩余电阻比（RRR）为1050。Ta层测得Tc为4.5K，RRR为45 × 140。我们用磁控溅射技术制备了Nb/AlOx-Al/Nb约瑟夫森结。Nb和Al层可以在不直接暴露于一对靶之间产生的等离子体区域的条件下在高密度等离子体下沉积。Nb层的转变温度和剩余电阻率分别为9.3K和3。Nb/AlOx-Al/NbJosephson结具有很低的亚带隙漏电流。