CONTROL OF STRUCTURE AND ELECTRICAL-PROPERTIES OF LEAD-ZIRCONIUM-TITANATE-BASED FERROELECTRIC CAPACITORS PRODUCED USING A LAYER-BY-LAYER ION-BEAM SPUTTER-DEPOSITION TECHNIQUE

It is demonstrated that the structure and electrical properties of Pb(ZrxTi1-x)O3(PZT)-based capacitors, involving RuO2 electrodes, can be controlled by depositing intermediate PbTiO3 (PT) layers at the PZT/electrode interfaces. Three different PZT-based capacitor systems were studied, namely: (a) RuO2/PZT/RuO2/(100)MgO, (b) RuO2/PZT/PT/RuO2/(100)MgO, and (c) RuO2/PT/PZT/PT/RuO2/(100)MgO. Electrical characterization of capacitor (a), without a PT layer, shows about 71% reduction in remanent polarization, while those with one (b) or two (c) PT layers present only 34% and 29% decrease in remanent polarization, after 1010 switching cycles. Electrical conduction measurements (current density versus time) have shown that ion beam sputter-deposited PZT-based capacitors with or without PT layers present about an order of magnitude (approximately 6 X 10(-9) A/cm2, at 100 s) smaller dc leakage current, for comparable physical and electrical parameters, than dc leakage characteristic of PZT sol-gel-based capacitors with RuO2 electrodes produced in our laboratory. Intermediate PT layers may help eliminate the formation of undesirable second nonferroelectric phases and/or charged defects at the PZT-electrodes interface in ion beam sputter-deposited PZT-based capacitors, which in tum results in improved electrical properties.