PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION OF YTTRIUM BARIUM COPPER OXIDE SUPERCONDUCTING MATERIAL

THE REPRODUCIBLE CRYSTAL GROWTH OF THIN FILMS WITH THE CORRECT STOICHIOMETRY AND APPROPRIATE MORPHOLOGY IS THE KEY TO THE COMMERCIALIZATION OF DEVICES INCORPORATING THIN FILM HIGH TEMPERATURE SUPERCONDUCTORS. MOCVD HAS THE POTENTIAL TO MEET THESE NEEDS COUPLED WITH RELATIVE EASE OF SCALING TOMANUFACTURING VOLUMES. HOWEVER, RECENT WORK ON MOCVD HAS BEEN PLAGUED BY TWO MAJOR LIMITATIONS: (1.) FILMS GROWN AT TEMPERATURES LESS THAN 800 DEGREES CENTIGRADE ARE AMORPHOUS MIXTURES OF OXIDES, FLUORIDES AND/OR BARIUM CARBONATE AND (2.) AS-DEPOSITED FILMS EXHIBIT CAULIFLOWER-LIKE MORPHOLOGY WHICH IS INDICATIVE OF LOW SURFACE MOBILITY GROWTH. SURFACE MOBILITIES CAN BE INCREASED WITHOUT ELEVATING THE TEMPERATURE OF THE SUBSTRATETHROUGH THE USE OF A PLASMA. MOREOVER, PLASMA ASSISTED LASER ABLATION, SPUTTERING AND REACTIVE EVAPORATION HAVE ALREADY BEEN USED FOR THE IN-SITU GROWTH OF SUPERCONDUCTING THIN FILMS AT TEMPERATURES AS LOW AS 400 DEGREES CENTIGRADE, EVEN WHEN BAF2 HAS BEEN USED AS THE BA PRECURSOR. THESE RESULTS SUGGESTS THAT PECVD MAY EFFECT THEIN-SITU GROWTH OF SUPERCONDUCTING THIN FILMS WITH THE EXISTING REAGENT TECHNOLOGY. THE GOAL OF THE PHASE I RESEARCH IS TO DEMONSTRATE THE PECVD OF IN-SITU SUPERCONDUCTING THIN FILMS OF YBACUO AT SUBSTRATE TEMPERATURES BELOW 600 DEGREES CENTIGRADE. PHASE II WILL FOCUS ON IN-SITU DIAGNOSTICS AND A MASS SELECTIVE DETECTOR WILL BE USED TO MEASURE THE ENERGY DISTRIBUTION OF THE INDIVIDUAL ION AND RADICAL CURRENTS AS WELL AS THE CONCENTRATION OF NEUTRALS PRESENT DURING GROWTH. THESE DATA WILL BE CRUCIAL TO FACILITATE SCALE-UP OF THE PECVD PROCESS IN PHASE III.