PROCESS MONITORING AND CONTROL DURING MOCVD OF FERROELECTRIC THIN FILMS

FERROELECTRICS (FE) HAVE A LARGE COMMERCIAL POTENTIAL AS PIEZOELECTRIC ELEMENTS, DIELECTRICS FOR CAPACITORS, AND IN OPTICAL GUIDED-WAVE DEVICES. MATERIALS PROCESSING HAS LIMITED APPLICATIONS IN MICROELECTRONICS AND PHOTONICS, HOWEVER, AND FEW METHODS ARE CAPABLE OF DEPOSITING HIGH QUALITY THIN FILMS COMPATIBLE WITH STANDARD SI INTEGRATED CIRCUIT PROCESS TECHNOLOGY. METALORGANIC CHEMICAL VAPOR DEPOSITION (MOCVD) IS A PROMISING TECHNOLOGY TO DEPOSIT SUCH THIN FILMS BECAUSE OF ITS LOW COST, ITS ABILITY TO ACHIEVE EPITAXIAL FILM GROWTH AT HIGH DEPOSITION RATES, AND THE EASE OF PROCESS SCALING TO COMMERCIAL VOLUMES. ALTHOUGH MANY TECHNOLOGICAL HURDLES HAVE BEEN OVERCOME, THE LACK OF ADEQUATE PROCESS MONITORING AND CONTROL IS BECOMING THE DOMINANT FACTOR SLOWING FUTURE DEVELOPMENT OF MOCVD TECHNIQUES FOR FE DEPOSITION. AT PRESENT, PROCESS SENSING IS NOT PERFORMED, AND PROCESS CONTROL CONSISTS OF RIGID CONTROL OF INPUT SETPOINTS. THIS PROPOSAL WILL APPLY IN-SITU FOURIER TRANSFORM INFRARED (FT-IR) SPECTROSCOPY FOR PROCESS MONITORING AND CONTROL OF MOCVD OF FE THIN FILMS. THE PROJECT COMBINES THE STATE-OF-THE-ART FT-IR TECHNIQUES OF ADVANCED FUEL RESEARCH, INC. (AFR) WITH THE ADVANCED MOCVD TECHNOLOGIES OF ADVANCED TECHNOLOGY MATERIALS, INC. (ATM). THIS RESEARCH WILL DEMONSTRATE THE CAPABILITY OF A SINGLE FT-IR INSTRUMENT TO MONITOR SIMULTANEOUSLY AND IN-SITU SUCH PARAMETERS AS GAS COMPOSITION, FILM COMPOSITION, AND SUBSTRATE TEMPERATURE. THIS DEMONSTRATION WILL TAKE PLACE ON ONE OF ATM'S ADVANCED MOCVD REACTOR CURRENTLY DEPOSITING BATIO3 THIN FILMS. THIS PROJECT WILL ALSO CORRELATE THE IR PROPERTIES OF THE THIN FILMS WITH THEIR ELECTRICAL, OPTICAL, AND DEVICE PROPERTIES TO IDENTIFY POTENTIAL CONTROL STRATEGIES. PHASE II OF THIS PROPOSAL WILL EXTEND THESE NEW RESULTS TO DEVELOP A RUGGED SPECTROMETER FOR USE ON LARGE SCALE DEPOSITION REACTORS. THE ANTICIPATED RESULT OF THIS PROPOSAL IS A RUGGED AND INEXPENSIVE SPECTROMETER THAT IS CAPABLE OF MONITORING AND CONTROLLING AN MOCVD REACTOR. SUCH A CONTROL TOOL WOULD IMPROVE THE QUALITY AND PERFORMANCE OF FERROELECTRIC MEMORY AND OPTO-ELECTRICAL DEVICES.