ION BEAM DEPOSITED FERROELECTRIC MEMORY FILMS

COMPUTER MEMORY ARRAYS ARE EXTREMELY VULNERABLE TO ELECTROMAGNETIC DISTURBANCES RESULTING FROM ACCIDENTAL OR HOSTILE ACTIONS. HARDENING AGAINST SUCH EFFECTS CAN BE IMPARTED EITHER BY ADDING EXTERNAL PROTECTION TO EXISTING SYSTEMS OR BY INCORPORATING SURVIVABILITY IN NEW DESIGNS. INHERENT HARDNESS CAN BE IMPARTED TO RANDOM ACCESS MEMORY ARRAYS BY USING THIN FILM FERROELECTRIC MATERIALS AS MEMORY ELEMENTS. THE DEVELOPMENT OF AN OPTICALLY MONITORED ION BEAM TECHNIQUE FOR THE DEPOSITION OF FERROELECTRIC THIN FILMS IS PROPOSED. THE NOVEL PRODUCTION METHOD WILL PRODUCE IN-SITU PEROVSKITE FERROELECTRIC THIN FILMS OF THE DESIRED CHEMICAL COMPOSITION AND CRYSTALLOGRAPHIC PROPERTIES ON SI AND GAAS SEMICONDUCTOR SUBTRATES WITHOUT POST DEPOSITION FIRING AND ANNEALING. SPECIFICALLY, THE PROCESS IS DESIGNED TO ADDRESS ISSUES SUCH AS CATION STOCHIOMETRY, PHASE STABILITY, FILM/SUBSTRATE EPITAXY, SUBSTRATE TEMPERATURE, PROCESS FINGERPRINTING, AND REAL-TIME FEEDBACK CONTROL. SINCE THE AS-DEPOSITED FERROELECTRIC FILMS ARE INTENDED FOR NONVOLATILE MEMORY APPLICATIONS, ENDURANCE AND RETENTION CHARACTEISTICS ARE EXTREMELY INPORTANT. A MORE THOROUGH CHARACTERIZATION OF BASIC ELECTRONIC MATERIALS PROPERTIES IS PROPOSED IN ADDITION TO THE USUAL FERROELECTRIC BEHAVIOR AND MEMORY RETENTION TRIALS. THE IMPLEMENTATION OF REAL-TIME FEEDBACK CONTROL, EXTENSION TO OTHER FERROELECTRIC SYSTEMS, SCALE-UP TO PRODUCTION TECHNOLOGY, AND INTERGRATION IN ACTIVE ARRAYS WOULD BE ADDRESSED IN THE PHASE II PROGRAM.