RETENTION CHARACTERISTICS OF A FERROELECTRIC MEMORY-BASED ON SRBI2(TA,NB)(2)O-9

The polarization decay process in SrBi2(Ta, Nb)(2)O-9 capacitors and r etention characteristics of a 288-bit ferroelectric memory device fabr icated from SrBi2(Ta, Nb)(2)O-9 were studied. The remanent polarizatio n decay at room temperature showed good linearity when plotted against logarithmic retention time over a wide range of 10(-3)-10(5) s. The d istribution of times to failure of a 288-bit memory was fit to a model having a linear relationship between log(log t(f)) and 1/T for the pe riod of infant failures and to the Arrhenius model having the form log t(f) vs 1/T for the period of random failures, where t(f) is the time to failure and T is the temperature. The activation energy was found to be 0.35 eV for infant failures and 1.15 eV for random failures. Pos sible causes for the difference in activation energies are discussed.