In this project, part of the joint ONR/NSF Program on Interfaces to Superconductors and supported by the Divisions of Chemistry, Materials Research, and Electrical and Communications Systems, Professors Chang and Marks of Northwestern University are studying the properties of interfacial growth regions between films of high-temperature superconducting (HTS) materials and insulating metal oxides. Atomic layer epitaxy (ALE) will be employed using a pulsed organometallic beam epitaxy system which is capable of growing metal oxide films with atomic layer precision but is also adaptable to large-scale low-temperature conformable metal oxide films growth as required in manufacturing. Superconductor/insulator heterostructures will be investigated under a variety of growth conditions and microstructures and interdiffusion properties will be evaluated by a variety of physical techniques, including various electron and atomic-force microscopies. Surface chemical processes will be directly monitored as a function of growth conditions during ALE. Improving the nature of interfaces in high-temperature superconducting materials and insulating metal oxides is a crucial barrier which must be surmounted before HTS materials can be successfully incorporated on a large scale into electronic device technologies. This study will provide the information needed to fabricate key structures for HTS-based electronics and an accurate evaluation of the potential of different growth techniques in this arena.
