IMPROVED FERROELECTRIC THIN FILMS FOR NONVOLATILE MEMORIES

EXTENSIVE SWITCHING AND MEMORY STUDIES HAVE BEEN MADE IN THE PAST ON THICK FILMS (10 TO 200 MM) OF DOPED XXXX FERROELECTRIC CERAMINCS. PARTICULAR COMPOSITIONS WITHIN THIS CERAMIC FAMILY WERE FOUND TO BE GREATLY SUPERIOR TO COMPARABLE THICK FILMS OF PZT. THE XXXX FERROELECTRIC THICK FILMS HAD ENDURANCES TWO TO FIVE ORDERS OF MAGNITUDE GREATER, LOWER COERCIVE VOLTAGES, LOWER PIEZOELECTRIC ACTIVITY AND HIGHER SIGNAL TO NOISE RATIO THAN THE EQUIVALENT PZT THICK FILMS. THIN FILMS (500 TO 10,000A) OF SELECTED COMPOSITIONS FROM THE XXXX FAMILY WILL BE FABRICATED USING A NEW SOL GEL PROCESS BASED ON ACETATE PRECURSORS. THE ELECTRICAL PROPERTIES OF THESE XXXX FILMS WILL BE EVALUATED FOR THEIR APPLICATION AS NONVOLATILE MEMORIES. BASED ON THE THICK FILM DATA, THESE XXXX THIN FILMS ARE EXPECTED TO HAVE ENDURANCES OF BETWEEN 10 X13 AND 10 X16 READ/WRITE CYCLES. THIS IS TWO TO FIVE ORDERS THIN XXXX FILMS ARE ALSO EXPECTED TO HAVE LOWER COERCIVE VOLTAGES, LOWER PIEZOELECTRIC ACTIVITY AND HIGHER SIGNAL TO NOISE RATIOS THAN THE BEST THIN PZT FILMS. ANTICIPATED BENEFITS/POTENTIAL COMMERCIAL APPLICATIONS - THE ANTICIPATED BENEFITS WOULD BE IMPROVED PERFORMANCE OF FERROELECTRIC NONVOLATILE I.C. MEMORIES. THE EXPECTED IMPROVEMENTS WOULD BE SUBSTANTIAL INCREASES OF ENDURANCE, SIGNAL TO NOISE RATIO AND SWITCHING SPEED. THESE IMPROVEMENTS ARE NECESSARY TO ALLOW FERROELECTRIC NONVOLATILE I.C. MEMORIES TO HAVE CAPACITIES OF UP TO AND IN EXCESS OF 1M BIT. SUCH MEMORIES HAVE MANY GENERAL PURPOSE AND SPECIALIZED GOVERNMENT AND COMMERCIAL APPLICATIONS. KEY WORDS - FERROELECTRIC, THIN FILM, ENDURANCE, PZT, SOL GEL, ACETATE PRECURSORS, NONVOLATILE MEMORIES.