IN-SITU OPTICAL DIAGNOSIS AND CONTROL OF PULSED LASER DEPOSITION OF HIGH TC SUPERCONDUCTOR THIN FILMS

ALTHOUGH MANY POTENTIAL TECHNOLOGIES EXIST FOR DEPOSITING EXOTIC THIN FILM DEVICES, CONTROLLING THE MATERIAL PROPERTIES HAS BEEN A MAJOR STUBLING BLOCK TO ACHIEVING SUCCESSFUL AND REPRODUCIBLE DEVICE PROPERTIES. IN THE CASE OF PULSED LASER DEPOSITION (PLD) OF HIGH TC SUPERCONDUCTOR FILMS, THE EMISSION OF THE PLASMA CAN BE CORRELATED WITH THE QUALITY OF FILMS DEPOSITED. BUT THIS MEASUREMENT PROVIDES ONLY A NECESSARY CONDITION. PROPER CONTROL WILL ALSO BENEFIT FROM ON-LINE MEASUREMENTS ON THE FILMS. THE INNOVATION PROPOSED HERE IS A MEASURMENT SYSTEM, WHICH COMBINES ULTRAVIOLET (UV) AND VISIBLE (VIS) EMISSION SPECTROSCOPY ON THE PLASMA, WITH FT-IR SPECTROSCOPY ON THE SUBSTRATE AND THIN FILM STRUCTURE. THIS COMBINATION WILL PROVIDE IN-SITU DATA RELATED TO THE CONCENTRATION, METAL STOICHIOMETRY, AND TEMPERATURE IN THE PLASMA, AND DATA ON THE FILM, INCLUDING OXYGEN STOICHIOMETRY, THICKNESS, AND TEMPERATURE. THE PROJECT WILL EMPLOY A STATE-OF-THE-ART PLD APPARATUS PRODUCING HIGH QUALITY YBA2CU3O7-X FILMS TO DEVELOP A COMBINED UV/VIS AND FT-IR SPECTROSCOPIC, ON-LINE MONITORING SYSTEM. THESE ON-LINE DATA WILL BE CORRELATED, WITH EACH OTHER AND WITH EX-SITU MEASUREMENTS, TO DETERMINE WHAT EMISSION CHARACTERISTICS ARE THE BEST INDICATORS OF GOOD FILM GROWTH. SPECIFICATIONS WILL BE DEVELOPED FOR A MONITORING SYSTEM TO BE CONSTRUCTED, TESTED, AND IMPROVED IN PHASE 2.