ION BEAM DEPOSITION OF RF SUPERCONDUCTING FILMS

THE DEVELOPMENT OF A THIN FILM VACUUM DEPOSITION PROCESS SUITABLE FOR THE FABRICATION OF SUPERCONDUCTING MICROWAVE CIRCUIT ELEMENTS BASED ON HIGH-TCYBA2CU307-X IS PROPOSED. THEDUAL ION BEAM FABRICATION METHOD WILL FACILITATE LOW-TEMPERATURE DEPOSITION OF DENSE EPITAXIAL FILMS OF UNIFORM STOICHIOMETRY ON SEMICONDUCTING OR INSULATING SUBSTRATES. AS SUCH, THIS TECHNOLOGY WILL ALLEVIATE MANY OFTHE COMPLICATIONS IMPLICIT IN PRESENT HIGH TC DEPOSITION TECHNIQUES SUCH AS HIGH PROCESS TEMPERATURES AND LIMITED APPLICABILITY OF COMPATIBLE SUBSTRATE MATERIALS. SINCE MOST HIGH PERFORMANCE DEVICES WILL REQUIRE THE ACHIEVEMENT OF HIGH CRITICAL CURRENT DENSITIES IN DEPOSITED FILMS, A METHOD IS PROPOSED BY WHICH CONTINUITY, EPITAXY, AND STOICHIOMETRY ARE ENCOURAGED IN THE GROWTH OF THE SUPERCONDUCTING FILM. ION AND NEUTRAL BEAM ASSISTED DEPOSITION WILL BE USED TO PROMOTE LOW TEMPERATURE EPITAXIALGROWTH ACHIEVING DENSE FILMS WITH THE DESIRED (001) TEXTURE AND APPROPRIATE CATION AND OXYGEN STOICHIOMETRY. THE DEPOSITION SCHEME WILL AVOID HIGH TEMPERATURE ANNEALING SO THAT HIGH CRITICAL CURRENT DENSITY FILMS CAN BE GROWN DIRECTLY ONTO A VARIETY OF IMPORTANT SUBSTRATES SUCH AS SI, GAAS AND A1203 WITHOUT HARMFUL INTERDIFFUSION EFFECTS. DEVICE STRUCTURES AND SUPERCONDUCTING PROPERTIES APPROPRIATE FOR JOSEPHSON JUNCTION DEVICES, MICROSTRIPS, ANDCHIRP FILTERS WILL BE SOUGHT.