EFFECTS OF MORPHOLOGICAL-CHANGES OF PT SRBI2TA2O9 INTERFACE ON THE ELECTRICAL-PROPERTIES OF FERROELECTRIC CAPACITOR/

Morphological changes have been observed at the interface of Pt/SrBi2T a2O9 (SBT) before and after annealing at 600 and 800 degrees C after d epositing Pt top electrode. We have investigated leakage currents, bre akdown voltages, and capacitances of Pt/SBT/Pt/SiO2/Si capacitor and P t/SBT/CeO2/Si gate structure. As a result, the leakage cut-rent densit y and capacitance are reduced from 10(-7) to 10(-8) A/cm(2) and 1.3 x 10(-10) to 8.5 x 10(-)11 F/cm(2), respectively; and breakdown voltage increases from 5 to 14 V after post-annealing. The reduced leakage cur rent density and increased breakdown voltage in the annealed samples a re due to the smooth morphology of the interface of Pt/SBT. In the as- deposited Pt top electrode on SET films, high electric field intensity is generated due to small are of the valleys filled with fine Pt grai ns, resulting in higher leakage current density than the post-annealed Pt top electrode. Although the total gate capacitance of the post-ann ealed sample is reduced by the non-contact area due to voids at the in terface of Pt/SBT, memory window of the ferroelectric gate is not infl uenced by such voids.