MEMORY EFFECTS OF SRBI2TA2O9 CAPACITOR ON SILICON WITH A SILICON-NITRIDE BUFFER

The memory effects of SrBi2Ta2O9 (SBT) films deposited on Si substrate s with an ultra-thin silicon nitride buffer layer have been investigat ed. The Capacitance-Voltage (C-V) measurements indicate low densities of interface traps, suggesting a good interface between the silicon ni tride buffer layer and the Si substrate. The C-V characteristics show hysteresis that is consistent with the polarization of the SET film, b ut opposite to that due to the electron injection/trapping effect. Whe n swept back and forth between -7V and +7V, a sizable hysteresis windo w of greater than or equal to 2V is observed. The results from a singl e-pulse programming experiment suggest that the switching time is shor ter than 8 ns, the shortest pulse available for the experiment. These results are all obtained on samples that exhibit remanent polarization s as low as 0.15 mu C/cm(2). Fatigue tests show only modest degradatio n of the memory window after 10(11) switching cycles. Results from for ming gas annealing experiments indicate no degradation up to 400 degre es C of annealing temperature.