Thin film processing and device fabrication in the Tl-Ca-Ba-Cu-O system

This paper reports on an obvious group of applications for HTS materials which is microwave and millimeter wave circuitry. Besides low loss, the unique features of these materials, such as flux flow, can be exploited. The authors have been concentrating on the Tl-Ca-Ba-Cu-O family of materials. The film growth techniques, lithographic processing methods and the characteristics of several devices the authors have developed will be presented. These devices include a flux flow-based transistor with demonstrated operation at over 35 GHz, real gain in a 50 Ω system and potentially useful non-linearities and impedance levels. A number of passive microwave components are under investigation to form a more complete HTS microwave technology group