IN-SITU DIAGNOSTICS FOR DEPOSITION OF HIGH T SUPERCONDUCTING FILMS

A RENEWED INTEREST IN THE APPLICATIONS OF SUPERCONDUCTIVITY HAS RESULTED FROM THE RECENT DISCOVERY OF PEROVSKITE-LIKE COPPER-OXIDE SUPERCONDUCTORS WITH TRANSITION TEMPERATURES ABOVE LIQUID NITROGEN TEMPERATURES. ALTHOUGH THE THIN FILMS AS DEPOSITED GENERALLY HAVE THE APPROPRIATE Y:BA:CU STOICHIOMETRY, A SUBSEQUENT HIGH TEMPERATURE (T>900 DEGREE CELCIUS) OXYGEN TREATMENT IS REQUIRED TO ACHIEVE THE CORRECT OXYGEN CONCENTRATION AND THE REQUIRED ORTHORHOMBIC CRYSTAL STRUCTURES. IN THIS STUDY, MONITORING TECHNIQUES ARE BEING DEVELOPED BY COUPLING IN-SITU DIAGNOSTICS WITH A UNIQUE LASER ABLATION TECHNIQUEFOR DEPOSITING FILM. TECHNIQUES BEING EVALUATED INCLUDE RAMAN, X-RAY TRANSFORM INFRARED (FT-IR) SPECTROSCOPIES. THIN FILM SAMPLES OF COPPERDIFFRACTION, AND FOURIER TRANSFORM INFRARED (FT-IR) SPECTROSCOPIES. THIN FILM SAMPLES OF COPPER OXIDE PEROVSKITE MATERIALS ARE BEING ANALYZED IN BOTH THE UNANNEALED, NON-SUPERCONDUCTING AND THE ANNEALED,SUPERCONDUCTING STATE USING THE ABOVE TECHNIQUES AT ROOM TEMPERATURE IN ORDER TO ESTABLISH BASELINE DATA. IN ADDITION, FT-IR EMISSION AND DIFFUSE REFLECTANCE TECHNIQUES ARE BEING USED TO MONITOR THE DEPOSITION PROCESS IN-SITU. WHEN SUCCESSFULLY DEMONSTRATED, THE FIRSTAPPLICATION OF THESE PRESENT MATERIALS (WHICH ARE GRANULAR) IS LIKELY TO BE IN THE AREA OF MICROELECTRONICS (IR DETECTORS, SUPERCONDUCTING INTERCONNECTS) RATHER THAN LARGER APPLICATIONS REQUIRING DUCTILE WIRES.