Fabrication of high-temperature superconducting nanobridges using atomic force microscopy

• Main Author: Elkaseh, Akram Abdulsalam
• Other Authors: Perold, W. J.
• Language: en
• Published: Stellenbosch : University of Stellenbosch 2008
• Subjects: Atomic force microscopy; Superconductivity; Josephson effect; Pulsed laser deposition; Dissertations > Electronic engineering; Theses > Electronic engineering
• Online Access: http://hdl.handle.net/10019.1/3324

Thesis (MEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. === The Josephson effect of high-temperature superconducting nanobridge structures is studied worldwide. Until now, nanobridges are generally fabricated with focused ion beam milling on planar thin films. These nanobridges are employed as weak links in superconducting quantum interference devices (SQUIDs) and used in superconducting flux flow transistors and devices. This project had two main objectives: to improve the sidewall angle of photoresist lines, with the aid of atomic force microscopy (AFM) nanolithography; and to fabricate hightemperature Josephson junctions by constricting superconductive YBCO lines on MgO substrates with AFM nanolithography. The entire fabrication process is explained including photolithography, deposition of the YBCO thin films with pulsed laser deposition (PLD), nanolithography and wet etching. Although the testing of the junctions did not show any Josephson behaviour, it could be demonstrated that nanobridge structures can successfully be created by AFM nanolithography. The entire fabrication process has been demonstrated in detail for the benefit of future research.