Interfaces in Ferroelectric Metal Oxide Heterostructures

1994 ◽  
Vol 343 ◽  
Author(s):  
R. Ramesh ◽  
J. Lee ◽  
V. G. Keramidas ◽  
D. K. Fork ◽  
S. Ghonge ◽  
...  
Keyword(s):  
Thin Film ◽  
Metal Oxide ◽  
Process Integration ◽  
Ferroelectric Properties ◽  
Ferroelectric Thin Film ◽  
Integration Process ◽  
Oxide Heterostructures ◽  
Ferroelectric Capacitor ◽  
Successful Solution

ABSTRACTRealization of a viable nonvolatile ferroelectric thin film memory technology hinges on the successful solution of the reliability problems associated with the ferroelectric capacitor concurrent with the integration of these materials with the appropriate Si-CMOS based drive electronics. This integration process introduces a variety of structural, chemical, ionic and electronic interfaces in the memory elements. In this paper, the influence of some of the interfaces on the ferroelectric properties and on the process integration is discussed.

New method of ferroelectric thin film characterization using a polarization instability invoked by a voltage cycling

2005 ◽  
Vol 902 ◽  
Author(s):  
Yuki Yamada ◽  
Susumu Shuto ◽  
Iwao Kunishima
Keyword(s):  
Thin Film ◽  
Ferroelectric Thin Film ◽  
Bipolar Pulse ◽  
Initial Value ◽  
Internal Defects ◽  
Ferroelectric Capacitor ◽  
Thin Film Characterization ◽  
Valence Change ◽  
And Storage ◽  
Stress Voltage

AbstractThe polarization change invoked by bipolar pulse cycling stress (voltage cycling) was investigated in detail for a Pt/PZT/Pt ferroelectric capacitor. The remnant polarization increased after voltage cycling, then, it decreased during storage and approached to the initial value. The estimated activation energy of the decay of the gained-polarization during the storage was 0.52eV. This value suggests that the valence change between Ti3+ and Ti4+ is the key of this phenomenon. The model where Ti-related defects pin the polarization was introduced to explain the result. Based on the findings and the model, a combination of voltage cycling and storage is useful to characterize internal defects. We propose this characterization method, named voltage cycling method, as an effective way to analyze internal defects in a ferroelectric capacitor.

The effects of PBB on the dielectric properties of BST film

2005 ◽  
Vol 902 ◽  
Author(s):  
Jin Cheol Kim ◽  
Jun Rok Oh
Keyword(s):  
Thin Film ◽  
Heat Treatment ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Magnetron Sputtering ◽  
Metal Oxide ◽  
Current Density ◽  
Energy Dispersive Spectrometer ◽  
Ferroelectric Thin Film ◽  
Rf Magnetron Sputtering

AbstractThe mixture of PbO-Bi2O3-B2O3 (PBB) were formed on the Ba0.5Sr0.5TiO3 (BST) film and the effects of PBB phase on the dielectric properties of the BST film were investigated. The amorphous PBB layer was deposited on the BST film using rf magnetron sputtering and diffused into the film by heat treatment. The PBB phase in BST film was identified by energy dispersive spectrometer (EDS). Dielectric properties of BST film were significantly improved after the diffusion of PBB. The leakage current density of BST film decreased from 3.24×10-5 A/cm2 to 9.45×10-8 A/cm2 at 1.5 V and the dielectric constant increased from 238 to 533. These results show that the diffusion of insulating metal oxide into the ferroelectric thin film can improve the dielectric properties of the film.

Study on Multilayered Electrodes for Ferroelectric Thin Film Capacitors

1994 ◽  
Vol 361 ◽  
Author(s):  
Ilsub Chung ◽  
J.K. Lee ◽  
Wan In Lee ◽  
C.W. Chung
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Electrical Properties ◽  
Physical Properties ◽  
Ferroelectric Properties ◽  
Ferroelectric Thin Film ◽  
Interfacial Engineering ◽  
Pzt Film ◽  
Thin Film Capacitors ◽  
Pzt Films

ABSTRACTThe ferroelectric properties of PZT on RuO2 electrodes were compared to those on RuOStudy on Multilayered Electrodes for Ferroelectric Thin Film Capacitors. It seems that the microstructure of PZT film plays an important role in the improvement of electrical properties. In particular, the change in the grain size of PZT film is responsible for the enhancement of the electrical properties. It was found in this study that films with smaller grain size had larger coercive fields. The exact dependence of the grain size on the hysteretic property is not fully understood at present. However, it is believed that the grain size affects both domain formation and domain pinning because of the influence of grain boundaries. The change in physical properties of PZT films due to the bottom electrode is understood in terms of interfacial modifications. Here we report on a method to modify physical properties of PZT films utilizing interfacial engineering.

MFMOS Capacitor with Pb5Ge3O11 Thin Film for One Transistor Ferroelectric Memory Applications

1999 ◽  
Vol 596 ◽  
Author(s):  
T. K. Li ◽  
S. T. Hsu ◽  
J. J. Lee ◽  
Y. F. Gao ◽  
M. Engelhard
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Ferroelectric Properties ◽  
Memory Window ◽  
Low Dielectric Constant ◽  
Ferroelectric Capacitor ◽  
Si Substrates ◽  
Low Dielectric ◽  
Low Leakage ◽  
Ferroelectric Hysteresis

AbstractA ferroelectric Pb5Ge3O11 thin film with a low dielectric constant is proposed for application in one transistor ferroelectric memories. A strong depolarization voltage on the ferroelectric capacitor with MIFSFET structures diminishes the remanent polarization significantly and, therefore, the low dielectric constant becomes very important to widen the memory window. A memory window of 3V was estimated for the MFMOS memory structure with 2000Å ferroelectric Pb5Ge3O11 and a 100Å gate oxide. In the second part of this paper, Pb5Ge3O11 films deposited on Ir/Ti/SiO2/Si substrates, by using MOCVD system, was demonstrated. Germanium ethoxide, Ge(OC2H5)4, and lead bis-tetramethylheptadione, Pb(thd)2, were used as the MOCVD precursors. The film composition, phase formation, microstructure and ferroelectric properties are reported. The c-axis oriented Pb5Ge3O11 thin films prepared by MOCVD and RTP post-annealing showed a square ferroelectric hysteresis loop with Pr of 2.83 μC/cm2 and EC of 49 kV/cm. A low leakage current of 7.5 × 10−7 A/cm2 at 100 kV/cm and low dielectric constant of 41 were also demonstrated.

Microstructure of thin film La0.5Sr0.5CoO3 electrode for microelectronics applications

1995 ◽  
Vol 53 ◽  
pp. 450-451
Author(s):  
Z. L. Wang ◽  
Jiming Zhang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Random Access ◽  
Chemical Vapor ◽  
Ferroelectric Thin Film ◽  
Ferroelectric Film ◽  
Epitaxial Relationship ◽  
Lattice Image ◽  
Ferroelectric Capacitor ◽  
Mocvd Technique

Increasing circuit densities in dynamic random access memories (DRAMs) is one of the major interests in microelectronics research. In a ferroelectric capacitor memory, conducting electrodes must make intimate and ohmic contact to both sides of the ferroelectric thin film. The bottom electrode serves as the substrate during growth and the top electrode is deposited on top of the ferroelectric film. Single crystalline La0.5Sr0.5CoO3 (LSCO) thin films, which are conductive and low electrical resistivity, have recently grown on both sides of Pb-Zr-Ti-O (PZT) ferroelectric film, which has shown a great potential for making fatigue-free small thickness storage capacitors. The present paper reports the microstructure studies of the LSCO thin films grown on MgO(00l) and LaAlO3(100) (LAO) substrates by the metalorganic chemical vapor deposition (MOCVD) technique.Cross-section specimens were made to examine the structure of the film and its relationship with the substrate. Select-area electron diffraction (SAD) and high-resolution lattice image show that the LSCO film has an epitaxial relationship with the MgO/LAO substrate.

All Epitaxial Babi4Ti4O15 - LaNiO3 Heterostructures

1998 ◽  
Vol 541 ◽  
Author(s):  
K. M. Satyalakshmi ◽  
A. Pignolet ◽  
M. Alexe ◽  
N. D. Zakharov ◽  
C. Harnagea ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Ferroelectric Properties ◽  
Hysteresis Loops ◽  
Ferroelectric Thin Film ◽  
Epitaxial Thin Films ◽  
Oxide Electrodes ◽  
Deposition Parameters ◽  
Ferroelectric Hysteresis ◽  
Ferroelectric Oxides

AbstractBismuth-based layer-structured ferroelectric oxides are gaining much attention for ferroelectric thin film applications due to their low fatigue. Epitaxial thin films of these layered ferroelectric oxides grown on epitaxial perovskite-type conducting oxide electrodes such as LaNiO3 are known to further improve the fatigue resistance. In this paper the ferroelectric properties of BaBi4Ti4O15films grown by pulsed laser deposition on epitaxial LaNiO3/SrTiO3(100) and LaNiO3/YSZ/Si(100) substrates are presented. BaBi4Ti4O15thin films with mixed a - and c - orientation exhibit ferroelectric hysteresis loops with a remanent polarization Pr of 2 μC/cm2and a coercive field Ec of about 75 kV/cm. The effect of the deposition parameters on thin film orientation, morphology and the ferroelectric properties of BBiT are discussed.

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