Nanomanufacturing of High-temperature Superconductor Circuits Using Focused Ion Beams

使用聚焦离子束进行高温超导体电路的纳米制造

• 批准号: 1635330
• 负责人: Shane Cybart
• 金额: $ 32.75万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-10-01 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635330&HistoricalAwards=false
• 关键词: Nanomanufacturing; temperature; Superconductor; Circuits; Using

The research objective is to investigate high-throughput, large-area nanomanufacturing of high-temperature ceramic oxide superconductor electronics. At liquid nitrogen temperature, ceramic oxide materials superconduct, i.e., they conduct electricity without offering resistance. These superconductors are anisotropic and the conductivity varies in different crystallographic directions, which complicates the manufacturing of Josephson junctions, the building-blocks of these circuits. Recent advances in focused ion beam technology has opened up a new resistless direct-write nanomanufacturing method for high-temperature superconductor electronics that has the potential to improve performance and reduce cost. This research involves several disciplines in science and engineering including nanofabrication, superconductor electronics, and cryogenics. The project will develop knowledge and skills in film growth, nanofabrication, mathematical modeling, advanced low noise electron transport measurement techniques as well as critical thinking to prepare students for careers in Science Technology Engineering and Mathematics. The Institute's Faculty Mentor Program will be utilized to create opportunities for women and underrepresented minority students. The superconductor electronics industry will be impacted in areas from high performance cryogenic computing to high temperature semiconductor amplifiers.The challenges to fabricating high transition temperature (high-Tc) ceramic oxide superconductor circuits are several. Its anisotropic crystal structure complicates the manufacture of Josephson junctions. The figure of merit for Josephson junctions scales exponentially with the circuit critical dimension. High performance devices require feature sizes in the sub-10 nanometer regime. Variation of even 1 nm can result in large fluctuations in the figure of merit. Despite these challenges many high-Tc junction manufacturing techniques have emerged over the last three decades but none is able to generate large numbers of Josephson junctions with high-yield and predictable properties. This award utilizes a finely focused 0.5 nm helium ion beam to directly modify the superconducting material for the precise fabrication of nanowires for Josephson junctions. The key to this method is that the material is very sensitive to the oxygen ordering in the crystal lattice which can be altered by light ion irradiation. Restricting this altered region to the nanoscale allows for the creation of in-plane tunneling barriers directly in the material with no resists or etching. The method is compatible with commercially available high-TC superconductor films on relatively inexpensive large area sapphire wafers. There are a number of variables in the parameter space for this process, such as beam current, dose, film thickness, and spatial Josephson junction dimensions. The goal is to study the impact of these parameters throughput, yield, and figure of merit uniformity.

本研究的目的是探讨高温陶瓷氧化物超导电子学的高通量、大面积奈米制造。在液氮温度下，陶瓷氧化物材料超导，即，它们导电而不产生电阻。这些超导体是各向异性的，电导率在不同的晶体方向上变化，这使得约瑟夫森结的制造复杂化，这些电路的构建块。聚焦离子束技术的最新进展为高温超导电子器件开辟了一种新的无阻直接写入纳米制造方法，该方法具有提高性能和降低成本的潜力。这项研究涉及科学和工程的几个学科，包括纳米纤维，超导电子学和低温学。该项目将开发薄膜生长，纳米纤维，数学建模，先进的低噪声电子传输测量技术以及批判性思维的知识和技能，为学生在科学技术工程和数学的职业生涯做好准备。将利用学院的教师导师方案为妇女和代表性不足的少数民族学生创造机会。从高性能低温计算到高温半导体放大器，超导电子工业将受到影响。制造高转变温度（高Tc）陶瓷氧化物超导电路的挑战有几个。它的各向异性晶体结构使约瑟夫森结的制造复杂化。约瑟夫森结的品质因数与电路临界尺寸成指数关系。高性能器件要求特征尺寸在10纳米以下。即使1 nm的变化也会导致品质因数的大幅波动。尽管存在这些挑战，但在过去三十年中出现了许多高Tc结制造技术，但没有一种能够产生大量具有高产率和可预测特性的约瑟夫森结。该奖项利用精细聚焦的0.5 nm氦离子束直接修改超导材料，用于精确制造约瑟夫森结的纳米线。这种方法的关键在于，材料对晶格中的氧有序非常敏感，这种有序可以通过轻离子照射来改变。将这种改变的区域限制在纳米级允许在没有抗蚀剂或蚀刻的情况下直接在材料中产生面内隧穿势垒。该方法与相对便宜的大面积蓝宝石晶片上的市售高TC超导膜兼容。在这个过程的参数空间中有许多变量，如束流，剂量，膜厚度和空间约瑟夫森结尺寸。我们的目标是研究这些参数的影响，吞吐量，产量和品质因数的均匀性。

项目成果

YBa $_2$ Cu $_3$ O $_{7-\delta }$ -CeO $_2$ -YBa $_2$ Cu $_3$ O $_{7-\delta }$ Multilayers Grown by Reactive Co-Evaporation on Sapphire Wafers

YBa $_2$ Cu $_3$ O $_{7-delta }$ -CeO $_2$ -YBa $_2$ Cu $_3$ O $_{7-delta }$ 通过反应共蒸发生长的多层膜

• DOI: 10.1109/tasc.2019.2898778
• 发表时间: 2019
• 期刊: IEEE Transactions on Applied Superconductivity
• 影响因子: 1.8
• 作者: Wang, Yan-Ting;Semerad, Robert;McCoy, Stephen J.;Cai, Han;LeFebvre, Jay;Grezdo, Holly;Cho, Ethan Y.;Li, Hao;Cybart, Shane A.
• 通讯作者: Cybart, Shane A.

Superconducting nano Josephson junctions patterned with a focused helium ion beam

• DOI: 10.1063/1.5042105
• 发表时间: 2018-07-09
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Cho, Ethan Y.;Zhou, Yuchao W.;Cybart, Shane A.
• 通讯作者: Cybart, Shane A.