Structural stability and kinetic processes in YBaCuO thin films and device structures

The recent discovery of a remarkable new family of high critical temperature (T/sub c/) superconducting oxides excites extraordinary interest and research activity worldwide. At present most of the research effort and all of the available published information relates to the fabrication of bulk samples from powders. The primary objective of this study is to achieve the deposition of high quality thin films for the investigation of materials characteristics and physical properties of relevance for the fabrication of superconducting tunnel junctions and devices. It is well known that the electronic structure of perovskites is extremely sensitive to the oxygen concentration, and recently it shows that high T/sub c/ perovskite materials are cycled reversibly between the semiconducting and superconducting state. Also observed is that thin films of this material are irreversibly degraded by water and by some processes commonly used in the fabrication of thin film device structures. Reported here are results on thin film deposition conditions, film structure and composition for 0.5μm high T/sub c/ Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub Y/ films. Also reported are the first results on the kinetics and reversibility of oxygen intercalation between 4170C and 6750C. Finally some preliminary measurements on tunnel junctions fabricated by different routes are presented