High temperature superconductor step-edge Josephson junctions using Ti-Ca-Ba-Cu-O

US5358928A · kind A · utility

Assignee

• Sandia Corporation · US

Inventors

• David S. Ginley · Evergreen, US
• Vincent M. Hietala · Bernalillo, US
• Gert K. G. Hohenwarter · Tarrytown, US
• Jon S. Martens · San Jose, US
• Thomas A. Plut · Albuquerque, US
• Chris P. Tigges · Albuquerque, US
• Gregory A. Vawter · Corrales, US
• Thomas E. Zipperian · Albuquerque, US

Key dates

• Filing date: Sep 22, 1992
• Grant date: Oct 25, 1994
• Expiry date: Sep 22, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S505/832

Abstract

A process for formulating non-hysteretic and hysteretic Josephson junctions using HTS materials which results in junctions having the ability to operate at high temperatures while maintaining high uniformity and quality. The non-hysteretic Josephson junction is formed by step-etching a LaAlO.sub.3 crystal substrate and then depositing a thin film of TlCaBaCuO on the substrate, covering the step, and forming a grain boundary at the step and a subsequent Josephson junction. Once the non-hysteretic junction is formed the next step to form the hysteretic Josephson junction is to add capacitance to the system. In the current embodiment, this is accomplished by adding a thin dielectric layer, LaA1O.sub.3, followed by a cap layer of a normal metal where the cap layer is formed by first depositing a thin layer of titanium (Ti) followed by a layer of gold (Au). The dielectric layer and the normal metal cap are patterned to the desired geometry.