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。氧化物超导体和绝缘子异质结构的超薄膜是通过原子层金属化学蒸气沉积法制备的。通过使用基于超声传感器和光谱椭圆法的原位监测来增强细膜制造的可重复性。2。约瑟夫森连接和平面型设备的组合增强了超导场效应3。由于扫描探针显微镜光刻制造而成的YBCO ThinFILM设备，观察到由于固有的Josephson连接而引起的异常电流电压特性。在5K.4时获得2.5mV的ICRN产品值。研究了两种可能导致ICRN产品值高的约瑟夫森连接的方法。使用分流电阻的超导体 - 绝缘体 - 渗透器结构，该结构是由隧道BAMER中局部状态形成的分流电阻的，比使用超级导体：非导体非正式金属超导管器结构更有前途。 PRBA2CU3O7（PBCO）中局部状态的物理性质及其与运输特性的相关性得到了充分阐明。厚度为6 nm至10 nm的坡道型连接处具有出色的约瑟夫森特征，并且在4.2 K时实现了超过2 mV的最大ICRN产品值。已经制造和测试了初步的单频量子逻辑电路，包括RS-flip flop和频率分离器。使用埋藏地面平面的坡道 - 边缘型约瑟夫森连接的频率分隔电路证实，在12 k时频率高达200 GHz。