Publication | Closed Access
Imprint in Ferroelectric Capacitors
143
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0
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1996
Year
Materials ScienceMaterials EngineeringElectrical EngineeringEngineeringFerroelectric ApplicationO 3NanoelectronicsApplied PhysicsFerroelectric CapacitorsFerroelectric MaterialsFerroelectric Random-access MemoryDonor DopingPolarization-voltage CharacteristicsSemiconductor MemoryMicroelectronicsPhase Change MemoryFunctional Materials
Thermal voltage shifts in Pb(Zr,Ti)O₃ capacitors arise partly from oxygen vacancy‑related defect dipoles in the film. Imprint originates from deep bulk Ti³⁺ centers and a composition‑dependent oxygen vacancy density. Voltage offsets in Pb(Zr,Ti)O₃ capacitors cause imprint, donor doping at Ti/Zr sites mitigates thermally‑induced shifts, and stress‑induced shifts vary with the Zr/Ti ratio.
We show that voltage offsets in the polarization-voltage characteristics of Pb(Zr, Ti)O 3 capacitors can lead to imprint in ferroelectric memory devices. The thermal-induced voltage shifts (internal bias field) are in part attributed to the role of oxygen vacancy-related defect dipoles throughout the film. In support of this, it is found that donor doping at the Ti(Zr) sites reduces the thermally-induced voltage shifts. The stress-induced voltage shifts are found to be dependent on the Zr/Ti cation ratio. This compositional dependence is explained by considering the role of deep bulk Ti 3+ centers and/or a compositional dependent oxygen vacancy density.