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

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.

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

MRS Proceedings ◽

10.1557/proc-415-183 ◽

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.

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

MRS Proceedings ◽

10.1557/proc-433-9 ◽

1996 ◽

Vol 433 ◽

Cited By ~ 7

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.

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

MRS Proceedings ◽

10.1557/proc-748-u12.8 ◽

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.

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

MRS Proceedings ◽

10.1557/proc-748-u6.5 ◽

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.

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SrTiO3 Films Prepared by MOCVD Using Novel Sr Source

MRS Proceedings ◽

10.1557/proc-361-287 ◽

1994 ◽

Vol 361 ◽

Cited By ~ 1

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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Characterization and leakage current density of radio frequency magnetron sputtered nanocrstalline SrTiO3 thin films

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2003.12.050 ◽

2004 ◽

Vol 264 (1-3) ◽

pp. 271-277 ◽

Cited By ~ 11

Author(s):

Moo-Chin Wang ◽

Fu-Yuan Hsiao ◽

Nan-Chun Wu

Keyword(s):

Thin Films ◽

Radio Frequency ◽

Leakage Current ◽

Leakage Current Density ◽

Current Density ◽

Radio Frequency Magnetron

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Orientation Control and Dielectric Properties of Ba0.6Sr0.4TiO3 Thin Films on Pt/Ti/SiO2/Si Substrates with PbO Seeding Layer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.741.11 ◽

2013 ◽

Vol 741 ◽

pp. 11-17

Author(s):

Xiao Hua Sun ◽

Ya Xia Qiao ◽

Shuang Hou ◽

Ying Yang ◽

Cai Hua Huang

Keyword(s):

Thin Films ◽

Dielectric Properties ◽

Leakage Current ◽

Leakage Current Density ◽

Current Density ◽

Precursor Solution ◽

Seeding Layer ◽

Bst Thin Films ◽

Si Substrates ◽

Bst Thin Film

Ba0.6Sr0.4TiO3 (BST) thin films were fabricated by solgel technique on Pt/Ti/SiO2/Si substrate without and with PbO seeding layer from precursor solutions with different concentrations. The crystal structure, surface morphology, dielectric properties and leakage current density of BST thin films are investigated as functions of the concentration of PbO precursor solution. Its found that the growth orientation of BST thin films with PbO seeding layer can be modulated through adjusting the concentration of PbO precursor solution. BST thin film with PbO seeding layer from 0.05 M precursor solution shows the highest dielectric constant and tunability, which may be attributed to the high crystallization and amplitude of the polarization in high (100) preferred orientated films. The leakage current density of BST films increases with the increasing concentration of PbO precursor solution and agrees well with the space-charge-limited current mechanism at room temperature.

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Enhancement of the Electrical Properties of BaTiO3 Films on GaAs Using Double Layer Structures

MRS Proceedings ◽

10.1557/proc-361-489 ◽

1994 ◽

Vol 361 ◽

Author(s):

L.H. Chang ◽

W.A. Anderson

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Electrical Properties ◽

Charge Density ◽

Leakage Current ◽

Leakage Current Density ◽

Double Layer ◽

Current Density ◽

Dielectric Constants ◽

Oxide Charge

ABSTRACTFerroelectric BaTiO3 thin films have been directly deposited on n-GaAs with carrier concentration of 5.3–8.2×1017/cm2. The BaTiO3 thin films with a thickness in the range of 80–120 nm were prepared by RF magnetron sputtering with a substrate temperature of 300°C. The as-deposited BaTiO3 films appeared to be amorphous with relative dielectric constants of around 15 and gave flat capacitance-voltage (C-V) curves, indicating poor interface properties and very high oxide charge density. After rapid thermal annealing (RTA) at 800°C for 60 sec, the relative dielectric constant of the BaTiO3 film increased to 82 and a sharp C-V curve was observed with oxide charge density of about 7×1012/cm2. However, the leakage current density increased from 4×10'11 A/cm2 for as-deposited BaTiO3 to 2×105 A/cm2 for RTA(800°C)-BaTiO3 at a field of 4×105 V/cm. By taking advantage of the best properties from both as-deposited amorphous BaTiO3 films (low leakage current density) and RTA(800°C)-BaTiO3 (high dielectric constant) the double layer structure was designed to enhance the electrical properties of the BaTiO3 films on GaAs. The most promising results in regards to the dielectric property and leakage current density are 76.5 and 9.7×109 A/cm2, respectively, for the double layer RTA(500°C)-BaTiO3 on RTA(800°C)-BaTiO3 structures.

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Electric properties of barium–strontium titanate thin films deposited by two-step radio-frequency sputtering

Journal of Materials Research ◽

10.1557/jmr.2001.0367 ◽

2001 ◽

Vol 16 (9) ◽

pp. 2680-2686 ◽

Cited By ~ 1

Author(s):

J. S. Fang ◽

C. T. Chang ◽

T. S. Chin

Keyword(s):

Thin Films ◽

Radio Frequency ◽

Layer Thickness ◽

Leakage Current ◽

Leakage Current Density ◽

Strontium Titanate ◽

Barium Strontium Titanate ◽

Current Density ◽

Dielectric Breakdown ◽

Barium Strontium

Barium-strontium titanate (BST) thin films were prepared by a two-step deposition using radio-frequency magnetron sputtering on Pt/Ti/SiO2-buffered Si(100) substrate. The initial BST layer thickness and intermediate annealing strongly affect the resultant electric properties of the two-step BST thin films. The optimal two-step BST films, with a first-layer thickness of 30 nm intermediate annealed at 610 °C under 1 torr oxygen. The dielectric breakdown and leakage current density of the two-step film are above 625 kV/cm and 9.5 nA/cm2 at 100 kV/cm, respectively, compared with 400 kV/cm and 17 nA/cm2 for the one-step films. We conclude that the two-step deposition dramatically improves dielectric breakdown and enhances leakage current density while keeping the dielectric constant uninfluenced.

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