Dielectric Properties of (Ba,Sr)TiO3 Thin Film Capacitors Fabricated on Alumina Substrates

2002 ◽  
Vol 748 ◽  
Author(s):  
I. P. Koutsaroff ◽  
A. Kassam ◽  
M. Zelner ◽  
P. Woo ◽  
L. McNeil ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Film Formation ◽  
Dissipation Factor ◽  
Processing Temperature ◽  
Polycrystalline Alumina ◽  
Annealing Conditions ◽  
Bst Films

ABSTRACTDouble layer (DL) Ba0.7Sr0.3TiO3 (BST) capacitors with Pt electrodes have been fabricated with similar growth conditions on different substrates. The substrates used in the present study were r-plane sapphire, polycrystalline alumina Al2O3 (99.6% and 96%), and glazed polycrystalline alumina. BST films were grown by metal-organic decomposition (MOD) method. By varying the annealing conditions which affects the formation of the crystalline structure, significant changes in the dielectric properties of the BST films have been observed. BST films were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Powder X-ray Diffractometer (PXRD). These observations showed that BST films grown at lower temperatures on alumina substrates exhibited the smallest grain size. BST films of the same thickness prepared under the same thermal processing conditions showed higher capacitance when grown on all types of alumina-based substrates compared to those deposited on control SiO2/Si. The higher capacitance on alumina was always associated with larger dissipation factor, and lower or similar leakage current density. The final tuning, of the dielectric properties of BST DL capacitors on non-silicon substrates, was correlated to the initial film formation temperature and post-annealing conditions of the BST films. The leakage current density, of DL BST capacitors fabricated on glazed alumina, becomes smallest when the BST processing temperature was lowered by 100 °C compared to the control SiO2/Si. The typical achieved leakage current density for 1500×1500 μm2 DL capacitors on glazed alumina was 3.8×10-9 A/cm2 at 250 kV/cm (36.5 fF/μm2), about 3 times lower than on SiO2/Si substrates (1.1×10-8 A/cm2 at 250 kV/cm, 31 fF/μm2).

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

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.

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.

Correlations of Ba1−xSrxTiO3 Materials and Dielectric Properties

1994 ◽  
Vol 361 ◽  
Author(s):  
Robert Tsu ◽  
Hung-Yu Liu ◽  
Wei-Yung Hsu ◽  
Scott Summerfelt ◽  
Katsuhiro Aoki ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Leakage Current ◽  
Processing Temperature ◽  
Polarization Current ◽  
Debye Relaxation ◽  
Capacitance Density ◽  
Materials Properties ◽  
Barium Strontium ◽  
Metal Organic ◽  
Bst Films

ABSTRACTThin film barium strontium titanate, Ba1−xSrxTiO3 (BST), has been deposited on Pt bottom electrodes using metal-organic decomposition (MOD). Optimization of BST electric properties, including capacitance density and leakage current, can be achieved by altering the chemical and microstructural attribute of the films. Dielectric properties of BST are strongly dependent on processing temperature, film thickness, composition, and microstructure, which are closely correlated with each other. Nucleation temperatures of BST range from 580°C – 650°C depending on film thicknesses. The chemical composition giving the highest dielectric constant is explained in terms of microstructure; capacitance increases with increasing grain size for the BST films in this study. Capacitance density of 50 fF/μ m2 and leakage current density < 100 nA/cm2 at 1.6 V can be achieved by optimizing BST materials properties. In addition, leakage conduction through the Pt/BST/Pt capacitor is shown to consist of polarization current resulting from Debye relaxation and true leakage current attributed to Schottky electron emission.

Capacitance Tunability of Magneto-electric Material:Cr2O3 using Ferromagnetic (La,Sr)MnO3 Electrode

2006 ◽  
Vol 966 ◽  
Author(s):  
Takeshi Yokota ◽  
Takaaki Kuribayashi ◽  
Takeshi Shundo ◽  
Keita Hattori ◽  
Yasutoshi Sakakibara ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Ferromagnetic Film ◽  
Low Leakage ◽  
Low Leakage Current ◽  
Ferromagnetic Electrode

ABSTRACTWe have investigated the dielectric properties of the Cr2O3 films using ferromagnetic electrode; (La0.66, Sr0.33)MnO3. The relationships between those properties and their crystallinity also have been investigated. The well crystallized sample was exhibited low leakage current density. Although all samples show capacitance decreasing by applying voltages, the decreasing ratio was the largest on the sample with lowest leakage current density. Since the Cr2O3 film with same leakage current density as that sample using non-magnetic electrode didn't show any capacitance changes by applying voltages, it is suggested that the dielectric properties of Cr2O3 film might be affected by the ferromagnetic film.

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.

3 kV Normally-Off 4H-SiC Buried Gate Static Induction Transistors (SiC-BGSITs)

2014 ◽  
Vol 778-780 ◽  
pp. 899-902 ◽  
Author(s):  
Akio Takatsuka ◽  
Yasunori Tanaka ◽  
Koji Yano ◽  
Norio Matsumoto ◽  
Tsutomu Yatsuo ◽  
...  
Keyword(s):  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Fabrication Process ◽  
Drain Voltage ◽  
Static Induction Transistors ◽  
Static Induction

3 kV normally-off SiC-buried gate static induction transistors (SiC-BGSITs) were fabricated by using an innovative fabrication process that was used by us previously to fabricate 0.7–1.2 kV SiC-BGSITs. The fabricated device shows the lowest specific on-resistance of 9.16 mΩ·cm2, compared to all other devices of the same class. The threshold voltage of this device was 1.4 V at room temperature and was maintained at values more than 1 V with normally-off characteristics at 200 °C. The device can block drain voltage of 3 kV with a leakage current density of 6.9 mA/cm2.

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.

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