Japanese Journal of Applied Physics · 1996 · 145 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceCeramic MaterialsElectronic MaterialsMaterials ChemistryDefects In Electronic MaterialsDopingFerroelectric CeramicsFerroelectric MaterialsMemory DevicesThin Film Electrical PropertiesCation Ratio EffectsDoping EffectsFerroelectric CapacitorsFerroelectric PropertiesFerroelectric Thin FilmsImprint EffectPolarization CharacteristicsThin Film Ferroelectrics
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.