Preparation and Characterization of Ba and Nb Substituted SrBi2Ta2O9 Compounds

2000 ◽  
Vol 655 ◽  
Author(s):  
Rasmi R. Das ◽  
P. S. Dobal ◽  
A. Dixit ◽  
W. Perez ◽  
M.S. Tomar ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Phase Formation ◽  
Perovskite Phase ◽  
Growth Conditions ◽  
Layered Perovskite ◽  
Phonon Modes ◽  
Si Substrates ◽  
Non Volatile Memory ◽  
Lower Temperature ◽  
Memory Applications

AbstractBi-layered ferroelectric compounds are considered most promising for non-volatile memory applications due to their high fatigue endurance. We have prepared SrBi2Ta2O9 powders with Ba (A sites) and Nb (B sites) substitutions using a novel solution based route. The powders were pressed and sintered at 1050°C to obtain high quality targets. Thin films were prepared using these ceramic targets on Pt/TiO2/SiO2/Si substrates using pulsed laser deposition (PLD) technique. The effects of growth conditions on phase formation as well as structural and electrical properties in films are studied. Initial results on films show good hysteretic characteristics. Though phase formation begins at much lower temperature, these films crystallize in a complete layered perovskite phase when prepared at 700°C. Optical phonon modes in these materials exhibit systematic variations with changing compositions. The changes in the Raman spectra are explained in terms of Ba and Nb substitutions at A and B sites, respectively. The temperature dependence of Raman spectra exhibits the substitution induced changes in the transition temperatures of these materials.

Dependence of Ferroelectric Properties of SBT Based Capacitors on the Electrode Material

1998 ◽  
Vol 541 ◽  
Author(s):  
S. Tirumala ◽  
S. O. Ryu ◽  
K. B. Lee ◽  
R. Vedula ◽  
S. B. Desu
Keyword(s):  
Thin Films ◽  
Electrode Material ◽  
Electrode Materials ◽  
Perovskite Phase ◽  
Ferroelectric Properties ◽  
Si Substrates ◽  
Non Volatile Memory ◽  
Metal Organic ◽  
Sputter Deposited ◽  
Memory Applications

AbstractThe effect of various electrode materials on the ferroelectric properties of SrBi2Ta2O9 (SBT) thin films has been investigated for non-volatile memory applications. Two sets of electrode structures, viz., Pt-Ir based and Pt-Rh based, were sputter deposited in-situ on Si substrates. SBT thin films were deposited on these electrodes using a metal-organic solution deposition technique followed by a post-deposition anneal at 750 °C in oxygen. Structural characterization revealed a polycrystalline nature with predominant perovskite phase in SBT thin films. Ferroelectric properties were studied in capacitor mode by depositing top electrodes, where the top electrode material is identical to that of the bottom electrode. Extensive analysis of the ferroelectric properties signify the important role played by the electrode material in establishing the device applicability is reported in this work.

Electrical Characterization and Microstructures of Y2O3-Doped Bi4Ti3O12 Thin Films

2013 ◽  
Vol 591 ◽  
pp. 208-211
Author(s):  
Min Chen ◽  
J. Liu ◽  
X.A. Mei
Keyword(s):  
Thin Films ◽  
Electrical Characterization ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
Si Substrates ◽  
Layered Perovskite Structure ◽  
Lower Temperature ◽  
Curie Temperature Tc

Y2O3-doped bismuth titanate (Bi4-xYxTi3O12: BYT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Y-doping into BIT caused a large shift of the Curie temperature ( TC ) from 675 °C to lower temperature and a improvement in dielectric property. The experimental results indicated that Y doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BYT film with x=0.75 were 28 μC/cm2 and 65 kV/cm, respectively.

Electrical Characterization and Microstructures of La-Doped Bi4Ti3O12 Thin Films

2011 ◽  
Vol 412 ◽  
pp. 318-321
Author(s):  
X.A. Mei ◽  
Min Chen ◽  
R.F. Liu ◽  
Y.H. Sun ◽  
J. Liu
Keyword(s):  
Thin Films ◽  
Electrical Characterization ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
La Doping ◽  
Si Substrates ◽  
Lower Temperature ◽  
La Doped

La-doped bismuth titanate (Bi4-xLaxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. La-doping into BIT caused a large shift of the Curie temperature ( TC ) from 675°C to lower temperature and a improvement in dielectric property. The experimental results indicated that La doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BLT film with x=0.75 were 20 μC/cm2 and 82kV/cm, respectively.

scholarly journals Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin-Wook Lee ◽  
Shaun Tan ◽  
Tae-Hee Han ◽  
Rui Wang ◽  
Lizhi Zhang ◽  
...  
Keyword(s):  
Defect Density ◽  
Solid Phase ◽  
Perovskite Phase ◽  
Light Emitting Diode ◽  
Growth Conditions ◽  
Layered Perovskite ◽  
Proof Of Concept ◽  
Semiconductor Films ◽  
Light Emitting ◽  
Crystalline Substrate

AbstractConventional epitaxy of semiconductor films requires a compatible single crystalline substrate and precisely controlled growth conditions, which limit the price competitiveness and versatility of the process. We demonstrate substrate-tolerant nano-heteroepitaxy (NHE) of high-quality formamidinium-lead-tri-iodide (FAPbI3) perovskite films. The layered perovskite templates the solid-state phase conversion of FAPbI3 from its hexagonal non-perovskite phase to the cubic perovskite polymorph, where the growth kinetics are controlled by a synergistic effect between strain and entropy. The slow heteroepitaxial crystal growth enlarged the perovskite crystals by 10-fold with a reduced defect density and strong preferred orientation. This NHE is readily applicable to various substrates used for devices. The proof-of-concept solar cell and light-emitting diode devices based on the NHE-FAPbI3 showed efficiencies and stabilities superior to those of devices fabricated without NHE.

Composition and Electrode Effects on the Electrical Properties of SrBi2Ta2O9

1997 ◽  
Vol 493 ◽  
Author(s):  
Darin T. Thomas ◽  
Norifumi Fujimura ◽  
S. K. Streiffer ◽  
Angus I. Kingon
Keyword(s):  
Remnant Polarization ◽  
Pyrochlore Phase ◽  
Hysteresis Loops ◽  
Layered Perovskite ◽  
Low Temperature Processing ◽  
Non Volatile Memory ◽  
Oxygen Gas ◽  
Memory Applications ◽  
Deposited Films ◽  
Deposition Conditions

AbstractSrBi2Ta2O9 has attracted great interest for non-volatile memory applications due to its minimal polarization fatigue. This paper describes systematic studies, using pulsed laser deposition, on the effect of deposition conditions on the Bi-Pt reaction and on the potential for low temperature processing. Changing the deposition temperature (Ts) and oxygen gas pressure during deposition can control the Bi content in the films. At a Ts of 600°C, the films have excess Bi and do not fully crystallize to SBT, resulting in poor remnant polarization (Pr). These films consist mostly of the pyrochlore phase, plus a small amount of disordered, c-oriented layered perovskite SBT. By annealing over 750°C, the films show improved Pr, but further Pt - Bi interactions occur. At a Ts of 700°C, the as-deposited films are fully crystallized and show saturated hysteresis loops. However, Bi deficiency through alloying results in reduced remnant polarization (2Pr = 7.0μC/cm2). Films on Ir/Pt show reduced electrode reactions and improved properties.

Electrical Characterization and Microstructures of Ce-Doped Bi4Ti3O12 Thin Films

2011 ◽  
Vol 492 ◽  
pp. 222-225
Author(s):  
J. Liu ◽  
M. Chen ◽  
X.A. Mei ◽  
Y.H. Sun ◽  
Chong Qing Huang
Keyword(s):  
Thin Films ◽  
Bismuth Titanate ◽  
Electrical Characterization ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
Si Substrates ◽  
Layered Perovskite Structure ◽  
Lower Temperature

Tb-doped bismuth titanate (Bi4-xCexTi3O12: BCT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Ce-doping into BIT caused a large shift of the Curie temperature (TC) from 675°C to lower temperature and a improvement in dielectric property. The experimental results indicated that Ce doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BCT film with x = 0.75 were 23 μC/cm2 and 80 kV/cm, respectively.

Electrical Characterization and Microstructures of Tb-Doped Bi4Ti3O12 Thin Films

2008 ◽  
Vol 368-372 ◽  
pp. 82-84
Author(s):  
Y.H. Sun ◽  
Min Chen ◽  
W.K. An ◽  
A.H. Cai ◽  
J. Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Characterization ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
Si Substrates ◽  
Layered Perovskite Structure ◽  
Lower Temperature ◽  
Curie Temperature Tc

Tb-doped bismuth titanate (BixTbyTi3O12: BTT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well-developed rod-like grains with random orientation. Tb doping into BIT caused a large shift of the Curie temperature (TC) from 675°C to lower temperature. The experimental results indicated that Tb doping into BIT result in a remarkable improvement in dielectric property.

MOCVD of SrBi2Ta2O9 for Integrated Ferroelectric Capacitors

1997 ◽  
Vol 493 ◽  
Author(s):  
Bryan C. Hendrix ◽  
Frank Hintermaier ◽  
Debra A. Desrocherst ◽  
Jeffrey F. Roedert ◽  
Gautam Bhandarit ◽  
...  
Keyword(s):  
Perovskite Phase ◽  
Random Access ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Fluorite Phase ◽  
Layered Perovskite ◽  
Process Pressure ◽  
Precursor Decomposition ◽  
Memory Applications ◽  
Ferroelectric Capacitors

ABSTRACTSrBi2Ta2O9 (SBT) is a promising material for ferroelectric random access memories (FERAM's) because it has high resistance to fatigue and imprint combined with low coercive field. Metalorganic chemical vapor deposition (MOCVD) offers the ability to produce high quality, conformai SBT films for both high and low density memory applications. An MOCVD process based on liquid delivery and flash vaporization has been developed which allows precise delivery of low vapor pressure precursors to the process. Precursor decomposition has been examined over a wide temperature range and the effects of process pressure have been examined. It is shown that Bi(thdb is superior to Bi(Ph)3 as a source of Bi, offering a wide decomposition window with compatible Sr and Ta precursors so that a simple, well-controlled, and repeatable process is achieved at low temperatures. Films with 90% conformallity have been grown on 0.6 μm structures with a 1:1 aspect ratio. The MOCVD process yields the fluorite phase, which is transformed to the ferroelectric layered perovskite phase upon annealing in oxygen. Dielectric constants (ε) of 200 and remanent polarization (2Pr)up to 16 μC/cm2 have been achieved on 150 mm wafers.

Electrical Characterization and Microstructures of Bi4-xGdxTi3O12 Thin Films

2014 ◽  
Vol 633 ◽  
pp. 257-260
Author(s):  
Min Chen ◽  
X.A. Mei ◽  
J. Liu
Keyword(s):  
Thin Films ◽  
Electrical Characterization ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
Si Substrates ◽  
Layered Perovskite Structure ◽  
Lower Temperature ◽  
Curie Temperature Tc

Gd2O3-doped bismuth titanate (Bi4-xGdxTi3O12: BGT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Gd-doping into BIT caused a large shift of the Curie temperature ( TC ) from 675 °C to lower temperature and a improvement in dielectric property. The experimental results indicated that Gd doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BGT film with x=0.75 were 28 μC/cm2 and 65 kV/cm, respectively.

Ferroelectric Properties and Microstructures of Bi4-x LuxTi3O12 Thin Films

2013 ◽  
Vol 833 ◽  
pp. 33-36 ◽  
Author(s):  
Min Chen ◽  
X.A. Mei ◽  
J. Liu
Keyword(s):  
Thin Films ◽  
Ferroelectric Properties ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Large Shift ◽  
Si Substrates ◽  
Layered Perovskite Structure ◽  
Lower Temperature ◽  
Lu Doping

Lu2O3-doped bismuth titanate (Bi4-xLuxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. Lu-doping into BIT caused a large shift of the Curie temperature ( TC ) from 675 °C to lower temperature and a improvement in dielectric property. The experimental results indicated that Lu doping into BIT also result in a remarkable improvement in ferroelectric property. The Pr and the Ec values of the BLT film with x=0.75 were 28 μC/cm2 and 65 kV/cm, respectively.

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