FLUX CONTROL IN JET VAPOR DEPOSITION VIA ATOMIC ABSORPTION SPECTROSCOPY

JET VAPOR DEPOSITION (JVD) USES SONIC GAS JETS IN "LOW VACUUM" IN A NOVEL APPROACH TO THIN FILM DEPOSITION. IT IS RAPIDLY APPROACHING COMMERCIAL PRODUCTION CAPABILITY IN WHICH REAL TIME MONITORING AND CONTROL OF DEPOSITION RATES WILL BE ESSENTIAL. JVD IS PARTICULARLY POWERFUL FOR DEPOSITION OF MULTICOMPONENT FILMS SUCH AS PZT AND RELATED FERROELECTRICS, FOR WHICH CONTROL OF INDIVIDUAL METAL FLUXES IS MOST VALUABLE. ACCORDINGLY, WE PROPOSE IN PHASE I TO EQUIP OUR JVD APPARATUS WITH A SENSITIVE, RELIABLE AND FAST OPTICAL TECHNIQUE, ATOMIC ABSORPTION, IN ORDER TO MONITOR GAS PHASE METAL ATOM CONCENTRATIONS IN THE EMERGING JET. IN OUR "LOW VACUUM" JETS, THIS IS EQUIVALENT TO A FLUX MEASUREMENT AND RELATES DIRECTLY TO DEPOSITION RATE. THE ABSORBANCE WILL BE MEASURED VIA GAS SHIELDED OPTICAL FIBER BUNDLES POSITIONED ON OPPOSITE SIDES OF THE JET. OUR GOAL IS TO USE THE INSTANTANEOUS VALUES OF ABSORBANCE AS AN INPUT FOR REAL TIME FEEDBACK CONTROL OF JET SOURCE CONDITIONS AND HENCE DEPOSITION RATES. IN PHASE I WE WILL DEMONSTRATE THE FEASIBILITY OF USING ATOMIC ABSORPTION TO TRACK METAL ATOM CONCENTRATIONS IN THE EMERGING JETS FOR THE SELECTED TEST CASES CU, BA, Y, TI AND AU. THESE TEST CASES ARE CONVENIENT FOR EXPERIMENTATION AND INCLUDE ELEMENTS OF IMPORTANT MULTICOMPONENT FILMS SUCH AS FERROELECTRICS AND HIGH T SUPERCONDUCTORS. THE MAIN BENEFIT WILL BE A GENERAL MEANS OF CONTROLLING DEPOSITION RATES IN JVD BY NONINVASIVE OPTICAL MEASUREMENT. THIS WILL MAKE POSSIBLE DEPOSITION OF IMPORTANT MULTICOMPONENT FILMS, E.G. FERROELECTRICS AND HIGH T SUPERCONDUCTORS, WITH MORE ACCURATELY CONTROLLED COMPOSITIONS. THESE MATERIALS HAVE COMMERCIAL VALUE AND ARE OF INTEREST TO THE FEDERAL GOVERNMENT.