Growth of Epitaxial Site-Engineered Bi4Ti3O12-Basded Thin Films by Mocvdand Their Characterization

2002 ◽  
Vol 748 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Tomohiro Sakai ◽  
Takayuki Watanabe ◽  
Minoru Osada ◽  
Masato Kakihana ◽  
...  
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Spontaneous Polarization ◽  
Chemical Vapor ◽  
The Other ◽  
Other Hand ◽  
La Substitution ◽  
Lower Temperature

ABSTRACTThin films of BIT, La-substituted BIT (BLT) and La- and V-cosubstituted BIT(BLTV) were epitaxially grown on SrRuO3//SrTiO3 substrates at 850°C by metalorganic chemical vapor deposition (MOCVD), and their electrical properties were systematically compared. All films on (100), (110) and (111)-oriented substrates were epitaxially grown with (001)-, (104)-/(014)-and (118) –preferred orientations, respectively. The leakage current density of the BLTV film was almost the same with that of the BLT film, but was smaller than that of BIT film, suggesting that the La substitution contributed to the decrease of the leakage current density especially in pseudoperovskite layer. Spontaneous polarization of the BLTV film was estimated to be almost the same with the BLT film but was smaller that that of the BIT film. This is explained by the decrease of Tc with the La substitution, while V did not contribute to the change of the Curie temperature (Tc ). On the other hand, the coercive field (Ec) value of the BLTV was smaller than that of the BIT and the BLT films. As a result, La substitution contributed to the decrease of the leakage current density together with the decrease of the spontaneous polarization due to the decrease of the Tc. On the other hand, V substitution contributes to the decrease of the defects that suppress the domain motion and increases the Ec value. Therefore, each substitution of La and V plays different roles and this contribution is remarkable for the films deposited at lower temperature.

Bismuth composition control of SrBi2TaNbO9 thin films by heat treating Bi2O3-inserted heterostructure

1999 ◽  
Vol 14 (7) ◽  
pp. 2986-2992 ◽  
Author(s):  
Yoon-Baek Park ◽  
Jeon-Kook Lee ◽  
Hyung-Jin Jung ◽  
Jong-Wan Park
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Ferroelectric Properties ◽  
Stoichiometric Composition ◽  
Heat Treating ◽  
The Other ◽  
Composition Control ◽  
Other Hand

Ferroelectric properties of SrBi2TaNbO9 (SBTN) thin films were changed by the amount of Bi content in SBTN. We proposed that the addition of excess Bi to the SBTN thin films could be accomplished by heat treating the SBTN/Bi2O3/SBTN heterostructure fabricated by the radio frequency magnetron sputtering method. The Bi composition was controlled by changing the thickness of the inserted Bi2O3 from 50 to 400Å in the SBTN/Bi2O3/SBTN heterostructure. As the thickness of Bi2O3 films was increased from 0 to 100 Å, the grain grew faster and the ferroelectric properties improved. On the other hand, when the thickness, of Bi2O3 films was thicker than 150 Å, the ferroelectric properties deteriorated. In particular, when a 400 Å Bi2O3 layer was inserted between SBTN films, a Bi2Pt phase appeared and the Bi2O3 films remained between SBTN films, resulting in poor ferroelectric properties. A Bi2Pt phase was formed by the reaction between the platinum bottom electrode and Bi2O3 films. On the other hand, the leakage current density of SBTN thin films decreased with the increase of inserted Bi2O3 film thickness. As the thickness of inserted Bi2O3 films was increased from 0 to 50 Å, leakage current density abruptly decreased because Bi content of the SBTN thin films was increased from 8 mol% deficient to stoichiometric composition. As the thickness of inserted Bi2O3 films increased from 100 to 400 Å, leakage current density gradually decreased because the remaining Bi2O3 layer in SBTN thin films increased.

Electrical and Structural Properties of SrTiO3 Thin Films Deposited by Plasma-enhanced Metalorganic Chemical Vapor Deposition

1997 ◽  
Vol 12 (4) ◽  
pp. 1160-1164 ◽  
Author(s):  
Nam-Kyeong Kim ◽  
Soon-Gil Yoon ◽  
Won-Jae Lee ◽  
Ho-Gi Kim
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Electric Field ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Chemical Vapor ◽  
Dissipation Factor ◽  
Si Substrates ◽  
Capacitance Voltage

The microstructure and electrical properties were investigated for SrTiO3(STO) thin films deposited on Pt/Ti/SiO2/Si substrates by PEMOCVD. The SrF2 phase existing in the STO films deposited at 450 °C influences the dielectric constant, dissipation factor, and leakage current density of STO films. The dielectric constant and dissipation factor of STO films deposited at 500 °C were 210 and 0.018 at 100 kHz, respectively. STO films were found to have paraelectric properties from the capacitance-voltage characteristics. Leakage current density of STO films at 500 °C was about 1.0 × 10-8 A/cm2 at an electric field of 70 kV/cm. The leakage current behaviors of STO films deposited at 500 and 550 °C were controlled by Schottky emission with applied electric field.

Low Temperature Preparation of High-Quality Pb(Zr,Ti)O3 Films by Metal Organic Chemical Vapor Deposition with High Reproducibility

2001 ◽  
Vol 688 ◽  
Author(s):  
Hiroshi Funakubo ◽  
Kuniharu Nagashima ◽  
Masanori Aratani ◽  
Kouji Tokita ◽  
Takahiro Oikawa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Process Window ◽  
High Quality ◽  
Low Temperature Preparation

AbstractPb(Zr,Ti)O3 (PZT) is one of the most promising materials for ferroelectric random access memory (FeRAM) application. Among the various preparation methods, metalorganic chemical vapor deposition (MOCVD) has been recognized as a most important one to realize high density FeRAM because of its potential of high-step-coverage and large-area-uniformity of the film quality.In the present study, pulsed-MOCVD was developed in which a mixture of the source gases was pulsed introduced into reaction chamber with interval. By using this deposition technique, simultaneous improvements of the crystallinity, surface smoothness, and electrical property of the film have been reached by comparing to the conventional continuous gas-supplied MOCVD. Moreover, this film had larger remanent polarization (Pr) and lower leakage current density. This is owing to reevaporation of excess Pb element from the film and increase of migration on the surface of substrate during the interval time.This process is also very effective to decrease the deposition temperature of the film having high quality. In fact, the Pr and the leakage current density of polycrystalline Pb(Zr0.35Ti0.65)O3 film deposited at 415 °C were 41.4 μC/cm2 and on the order of 10−7 A/cm2 at 200 kV/cm. This Pr value was almost the same as that of the epitaxially grown film deposited at 415 °C with the same composition corrected for the orientation difference. This suggests that the polycrystalline PZT film prepared by pulsed-MOCVD had the epitaxial-grade ferroelectric properties even through the deposition temperature was as low as 415 °C. Moreover, large “process window” comparable to the process window at 580 °C, above 150 °C higher temperature and was widely used condition, was achieved even at 395°C by the optimization of the deposition condition.

Preparation and Characterization Of SrTio3 Thin Films Using ECR Plasma Assisted MOCVD

1995 ◽  
Vol 415 ◽  
Author(s):  
Joon Sung Lee ◽  
Han Wook Song ◽  
Dae Sung Yoon ◽  
Byung Hyuk Jun ◽  
Byoung Gon Yu ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Oxygen Plasma ◽  
Grain Structure ◽  
Breakdown Field ◽  
Ecr Plasma ◽  
Step Coverage

ABSTRACTSrTiO3 thin films were prepared on Si(p-type 100) and Pt/SiO2/Si substrates using ECR plasma (or without ECR plasma) assisted MOCVD. Sr(TMI-D)2 and Ti-isopropoxide were used as Sr and Ti metal organic sources, respectively. Perovskite SrTiO3 films were obtained at relatively low temperature of 500°C (using ECR oxygen plasma. Experimental results indicated that higher deposition temperature and ECR oxygen plasma increase the crystallinity, the dielectric constant and the leakage current density. The dielectric constant and the dielectric loss were 222 and 0.04, respectively, for 1234 Å thin SrTiO3 film (Sr/(Sr+Ti)=0.5). The leakage current density was 3.78 × 10−7 A/cm2 at 1.0V, and the dielectric breakdown field was 0.57MV/cm. SEM analyses showed that SrTiO3 films have a uniform and fine grain structure. In terms of step coverage, a lateral step coverage of 50% at 0.8 μm step (the aspect ratio was 1) was obtained with the thickness uniformity of ± 0.5% and the composition uniformity of ±1.2% at 4′′ wafer.

Structure, ferroelectric/magnetoelectric properties and leakage current density of (Bi0.85Nd0.15)FeO3 thin films

2011 ◽  
Vol 509 (17) ◽  
pp. 5326-5335 ◽  
Author(s):  
A.Z. Simões ◽  
L.S. Cavalcante ◽  
F. Moura ◽  
E. Longo ◽  
J.A. Varela
Keyword(s):  
Thin Films ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Magnetoelectric Properties

Preparation and Characterization of (Sr1−xTix)O3 and (Ba1−xSrx)TiO3 Thin Films using ECR Plasma Assisted MOCVD

1996 ◽  
Vol 433 ◽  
Author(s):  
Kwangsoo No ◽  
Joon Sung Lee ◽  
Han Wook Song ◽  
Won Jong Lee ◽  
Byoung Gon Yu ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Breakdown Field ◽  
Carrier Gas ◽  
Ecr Plasma

AbstractBa(TMHD)2, Sr(TMHD)2 and Ti-isopropoxide were used to fabricate the (SrxTi1 x)O3 and (Ba1 x Srx)TiO3 thin films. The decomposition and degradation characteristics of Ba(TMHD)2 and Sr(TMHD)2 with storage time were analyzed using a differential scanning calorimeter (DSC). The thin films were fabricated on Si(p-type 100) and Pt/SiO2/Si substrates with Ar carrier gas using ECR plasma (or without ECR plasma) assisted MOCVD. Experimental results showed that the ECR oxygen plasma increased the deposition rate, the ratio of Sr/Ti, the dielectric constant and the leakage current density of the film. The dependency of the crystallinity and the electrical properties on the Sr/Ti ratio of films were investigated. However, almost of the films deposited with Ar carrier gas had slightly high dielectric loss and high leakage current density and showed non-uniform compositional depth profiles. NH3 gas was also used to decrease the degradation of the MO-sources. Mass spectra in-situ monitoring of source vapors in ECR-PAMOCVD system were obtained. By introducing NH3 as a carrier gas, a significant improvement was achieved in the volatility and the thermal stability of the precursors, and the vaporization temperatures of the precursors were reduced compared to Ar carrier gas. The uniform compositional depth profile, less hydrogen and carbon content and the good electrical properties of (SrxTi1−x)O3 thin films were obtained with NH3 carrier gas. The (Ba1−xSrx)TiO3 thin film were fabricated to have very fine and uniform microstructure, the dielectric constant of 456, the dielectric loss of 0.0128, the leakage current density of 5.01 × 10−8A/cm2 at 1V and the breakdown field of 3.65MV/cm.

Preparation of Bi2SiO5-SrBi2Ta2O9 Ferroelectric Thin Films by RF Magnetron Sputtering

2002 ◽  
Vol 748 ◽  
Author(s):  
Shin Kikuchi ◽  
Hiroshi Ishiwara
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Remnant Polarization ◽  
Rf Magnetron Sputtering ◽  
Ferroelectric Thin Films ◽  
Ferroelectric Films ◽  
Typical Composition

ABSTRACTSi-added SrBi2Ta2O9 (SBT) ferroelectric films were prepared by RF magnetron sputtering on a Pt/Ti/SiO2/Si (100) structure. The films were deposited at temperatures below 100°C for preventing Bi evaporation and crystallized at 800°C in air. A typical composition was Sr0.79Bi2.37Ta2.00Si0.2Ox. The remnant polarization value(2Pr) of the Si-added SBT film was 16C/cm2 and leakage current density was 5×10-8A/cm2. The current density was significantly decreased by adding Si atoms.

Influence of Ta2O5, TiO2, and ZrO2 Interfacial Layers on Structural and Electrical Properties of Laser Ablated Ba0.5Sr0.5TiO3 Thin Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Suprem R. Das ◽  
Rasmi R. Das ◽  
P. Bhattacharya ◽  
Ram S. Katiyar
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Buffer Layers ◽  
Bst Thin Films ◽  
Interfacial Layers ◽  
Average Grain Size ◽  
Structural And Electrical Properties

ABSTRACTPulsed laser deposition technique was used to fabricate Ba0.5Sr0.5TiO 3 (BST) thin-films on Pt/TiO 2/SiO2/Si substrates. The influence of thin interfacial layers of Ta2O5, TiO2, and ZrO2, on the structural and electrical properties of BST thin films was investigated. Insertion of interfacial layers does not affect the perovskite phase formation of BST thin films. Buffer layers helped to make uniform distribution of grains and resulted in a relative increase in the average grain size. The dielectric tunability of BST thin films was reduced with the presence of buffer layers. A BST thin film having a dielectric permitivity of 470 reduced to 337, 235 and 233 in the presence of Ta2O5, TiO2, and ZrO2 layers, respectively. The reduction of the relative dielectric permittivity of BST films with the insertion of interfacial layers was explained in terms of a series capacitance effect, due to the low dielectric constant of interfacial layers. The TiO2 layer did not show any appreciable change in the leakage current density. Deposition of thin Ta2O5 and ZrO2 interfacial layer on top of Pt reduced the leakage current density by an order of magnitude.

SrTiO3 Films Prepared by MOCVD Using Novel Sr Source

1994 ◽  
Vol 361 ◽  
Author(s):  
Hideaki Yamauchi ◽  
Takafumi Kimura ◽  
Masao Yamada
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Thick Films ◽  
Relative Dielectric Constant ◽  
Si Substrates ◽  
Vaporization Temperature

ABSTRACTSrTiO3 thin films have been prepared by MOCVD. A novel Sr source of Sr(DPM)2-tetraen2 was used to stabilize source delivery and to reduce the vaporization temperature of Sr source. Films were deposited on Pt/Ta/Si substrates at deposition temperatures from 450 °C to 600 °C. The relative dielectric constant was about 220 at the deposition temperatures from 550 °C to 600 °C for as-deposited 90-nm-thick films. The leakage current density was in the range of 10−7 A/cm2, typically.

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