Growth, Evaluation And Modeling Of High Tc Superconducting Multilayer Structures

Residual stress in thin-film materials resulting from thermal and chemical strains is a continuing problem in the synthesis of superconducting thin films. The probelm exists not only in the superconducting layers, but also in the dielectric layer used as a buffer. Models that can analyze and predict the film stresses and accompanying mechanical failure are extremely useful as a starting point in the design of a multilayer circuit. The present program jointly proposed by Excel Superconductor, Inc. and North Carolina State University addresses this need. Computer modeling of typical multilayer structures containing superconducting thin films, dielectric layers and metal layers will be model as well as provide feed back information to improve the model. The proposed research will enable us to determine the key factors responsible for the stresses developed in the processing of the films, mode of failure of the films by introduction of flaws and voids. This information will forecase the success of any particular HTS based thin-film device. In Phase I such a study will be carried out for TBCO/LaA103 and metal/TBCO/YSZ/Si systems, issues for Phase II will be identified for the use of the model for other systems. ANTICIPATED BENEFITS: When fully developed, the model could predict the mechanical performance of multilayer thin-film structures in a particular geometry. This will aid the selection of mechanically correct circuit designs suitable for any particular application like semiconductor interconnects, SQUIDS and hybrid electronic circuits.