权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Fabnication of Superconductor/Insulator/Superconductor Trilayer Tunnel Junction Devices by Atomic Layer MOCVD

原子层MOCVD制备超导/绝缘体/超导三层隧道结器件

基本信息

批准号：
08555004
负责人：
ODA Shunri
金额：
$ 8.45万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08555004/
关键词：
Oxide Superconductors Superconducting Devices MOCVD Atomic Layer Epitaxy Josephson Junction Resonant Tunneling Localized States In Situ Ellipsometry

项目摘要

1. Ultrathin films of oxide superconductors and insulator heterostructures were prepared by the atomic layer metalorganic chemical vapor deposition method. Reproducibility of thinfilms fabrication was enhanced by using in situ monitoring based on ultrasonic transducers and spectroscopic ellipsometry.2. Superconducting field effect was enhanced by the combination of Josephson junctions and planar type devices.3. Anomolous current voltage characteristics due to intrinsic Josephson junctions were observed in YBCO thinfilm devices fabricated by scanning probe microscopy lithography. IcRn product value of 2.5mV were obtained at 5K.4. Two possible approaches for realizing overdamped Josephson junctions with a high IcRn product value were investigated. The use of an superconductor-insulator-superconductor structure with a shunt resistor that was formed by quasiparticle current paths via localized states in the tunnel bamer was concluded to be more promising than the use of an superconductor-normal metal-superconductor structure. The physical nature of localized states in PrBa2Cu3O7 (PBCO) and its relevance to transport properties were fully clarified. Ramp-edge-type junctions with a Co-doped PBCO barrier ranging from 6 nm to 10 nm in thickness exhibited excellent Josephson characteristics, and the maximum IcRn product value exceeding 2 mV at 4.2 K has been realized. Preliminary single-flux-quantum logic circuits including an RS- flip flop and a frequency divider have been fabricated and tested. The frequency divider circuit utilizing ramp-edge-type Josephson junctions with a buried groundplane was confirmed to operate correctly up to 200 GHz in frequency at 12 K.

1.用原子层金属有机化学气相沉积法制备了氧化物超导体和绝缘体异质结构的超薄膜。采用基于超声换能器和椭圆偏振光谱的原位监测技术，提高了薄膜制备的再现性.约瑟夫森结与平面型器件的结合增强了超导场效应.在用扫描探针显微镜光刻法制备的YBCO薄膜器件中，观察到由于本征约瑟夫森结引起的反常电流-电压特性。在5K.4下获得2.5mV的IcRn乘积值。研究了两种实现高IcRn积值过阻尼约瑟夫森结的可能途径。使用超导体-绝缘体-超导体结构与由准粒子电流路径通过隧道巴默尔中的局域态形成的分流电阻器被认为比使用超导体-正常金属-超导体结构更有前途。充分阐明了PrBa_2Cu_3O_7（PBCO）中局域态的物理本质及其与输运性质的关系。具有厚度为6 nm至10 nm的Co掺杂PBCO势垒的斜坡边缘型结表现出优异的约瑟夫森特性，并且在4.2 K下实现了超过2 mV的最大IcRn乘积值。初步的单通量量子逻辑电路，包括RS触发器和分频器已经制造和测试。利用斜坡边缘型约瑟夫森结与埋地平面的分频器电路被证实，正确的工作频率高达200 GHz，在12 K。