Office of Research, UC Riverside
Shane Cybart
Associate Professor
Electrical & Computer Eng Dept
cybart@ucr.edu
(951) 827-5448


Nanomanufacturing of high-transition temperature oxide superconductorcircuits with gas field ion sources

AWARD NUMBER
008547-002
FUND NUMBER
33305
STATUS
Active
AWARD TYPE
3-Grant
AWARD EXECUTION DATE
10/11/2016
BEGIN DATE
10/1/2016
END DATE
9/30/2019
AWARD AMOUNT
$327,469

Sponsor Information

SPONSOR AWARD NUMBER
1664446
SPONSOR
NATIONAL SCIENCE FOUNDATION
SPONSOR TYPE
Federal
FUNCTION
Organized Research
PROGRAM NAME

Proposal Information

PROPOSAL NUMBER
17030295
PROPOSAL TYPE
New
ACTIVITY TYPE
Basic Research

PI Information

PI
Cybart, Shane
PI TITLE
Other
PI DEPTARTMENT
Mechanical Engineering
PI COLLEGE/SCHOOL
Bourns College of Engineering
CO PIs

Project Information

ABSTRACT

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.
(Abstract from NSF)