Plasma Enhanced Mocvd of BaTiO3 Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Peter C. Van Buskirk ◽  
Robin Gardiner ◽  
Peter S. Kirlin ◽  
Salora Krupanidhi ◽  
Steven Nutt
Keyword(s):  
Single Phase ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Polycrystalline Films ◽  
Fine Grained ◽  
Selected Area Electron Diffraction ◽  
Electro Optic ◽  
Ir Reflectance ◽  
High Dielectric ◽  
Very High

AbstractBulk BaTiO3 has a large linear electro-optic coefficient and a very high dielectric constant. We report results obtained for two different MOCVD processes designed to deposit BaTiO3 films with properties suitable for nonlinear electro-optic or high charge storage applications. Epitaxial BaTiO3 films have been grown on NdGaO3 [100] substrates using a high temperature thermal process; the substrate temperature was 1000°C and the total pressure was 4 torr. Selected area electron diffraction (SAED) measurements indicate highly textured, single phase films on the NdGaO3 substrate which are predominantly [100] oriented. Fine grained polycrystalline films have been grown on Pt at 600°C by plasma-enhanced metalorganic chemical vapor deposition (PEMOCVD). Specular IR reflectance was used to determine the concentration of BaCO3 in the film, which was significantly reduced by the plasma. The polycrystalline films had dielectric constants as large as 300 and resistivities exceeding 5 x 108 Ω-cm at room temperature.

Effects of Electrode on Dielectric Properties of Barium Iron Niobate Ceramics Doped with Gallium Oxide

2016 ◽  
Vol 675-676 ◽  
pp. 548-551
Author(s):  
Kachaporn Sanjoom ◽  
Thanatep Phatungthane ◽  
Denis Russell Sweatman ◽  
Sukum Eitssayeam ◽  
Chamnan Randorn ◽  
...  
Keyword(s):  
Frequency Dispersion ◽  
Solid State Reaction Method ◽  
Dielectric Constants ◽  
Dielectric Measurement ◽  
All Ceramic ◽  
Ag Paste ◽  
High Dielectric ◽  
Paste Electrode ◽  
Very High ◽  
Iron Niobate

Ba (Fe0.8Ga0.2)0.5Nb0.5O3 ceramics were synthesized via a solid state reaction method. The Raman spectrum analysis indicated that the sample presented a cubic structure. Dielectric measurement on the ceramics with Ag-paste and Au-sputtered electrodes showed that all ceramic samples exhibited very high dielectric constants with a strong frequency dispersion. The Au-sputtered electrode samples presented higher dielectric tunability the dielectric constant than Ag-paste electrode samples.This behaviour was related with the electrode effect, occured in the studied samples.

scholarly journals Structural and Optical Characteristics ofγ-In2Se3Nanorods Grown on Si Substrates

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
M. D. Yang ◽  
C. H. Hu ◽  
S. C. Tong ◽  
J. L. Shen ◽  
S. M. Lan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Bandgap Energy ◽  
Si Substrates ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Metal Organic ◽  
Organic Chemical Vapor Deposition

This study attempted to grow single-phaseγ-In2Se3nanorods on Si (111) substrates by metal-organic chemical vapor deposition (MOCVD). High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) confirmed that the In2Se3nanorods are singularly crystallized in theγphase. The photoluminescence ofγ-In2Se3nanorods at 15 K was referred to as free and bound exciton emissions. The bandgap energy ofγ-In2Se3nanorods at room temperature was determined to be~1.99 eV, obtained from optical absorption.

Effect of Electrode on Electrical and Ferroelectric Behavior of Modified BNT Lead-Free Ceramics

2016 ◽  
Vol 872 ◽  
pp. 109-113
Author(s):  
Ratabongkot Sanjoom ◽  
Pharatree Jaita ◽  
Chatchai Kruea-In ◽  
Denis Russell Sweatman ◽  
Tawee Tunkasiri ◽  
...  
Keyword(s):  
Low Frequency ◽  
Rhombohedral Phase ◽  
Dielectric Constants ◽  
Dielectric Measurement ◽  
Lead Free ◽  
Pure Perovskite Structure ◽  
Ferroelectric Behavior ◽  
Lead Free Ceramics ◽  
High Dielectric ◽  
Very High

In this research, the effect of electrode type on electrical i.e. dielectric and ferroelectric behavior of 0.94BNT-0.06BT ceramics was studies. The ceramics were prepared by conventional mixed oxide method. The sample exhibited a pure perovskite structure with rhombohedral phase. For dielectric measurement, the ceramics with Ag pasted electrodes exhibited very high dielectric constants and good responding with low frequency than Au sputtered electrode.

scholarly journals Prospects for the Development of High Energy Density Dielectric Capacitors

2021 ◽  
Vol 11 (17) ◽  
pp. 8063
Author(s):  
Andrew Burke
Keyword(s):  
Dielectric Constant ◽  
Energy Density ◽  
Breakdown Strength ◽  
High Energy ◽  
Dielectric Constants ◽  
Polymer Materials ◽  
High Energy Density ◽  
Effective Dielectric Constant ◽  
High Dielectric ◽  
Very High

In this paper, the design of high energy density dielectric capacitors for energy storage in vehicle, industrial, and electric utility applications have been considered in detail. The performance of these devices depends primarily on the dielectric constant and breakdown strength characteristics of the dielectric material used. A review of the literature on composite polymer materials to assess their present dielectric constants and the various approaches being pursued to increase energy density found that there are many papers in which materials having dielectric constants of 20–50 were reported, but only a few showing materials with very high dielectric constants of 500 and greater. The very high dielectric constants were usually achieved with nanoscale metallic or carbon particles embedded in a host polymer and the maximum dielectric constant occurred near the percolation threshold particle loading. In this study, an analytical method to calculate the dielectric constant of composite dielectric polymers with various types of nanoparticles embedded is presented. The method was applied using an Excel spreadsheet to calculate the characteristics of spiral wound battery cells using various composite polymers with embedded particles. The calculated energy densities were strong functions of the size of the particles and thickness of the dielectric layer in the cell. For a 1000 V cell, an energy density of 100–200 Wh/kg was calculated for 3–5 nm particles and 3–5 µ thick dielectric layers. The results of this study indicate that dielectric materials with an effective dielectric constant of 500–1000 are needed to develop dielectric capacitor cells with battery-like energy density. The breakdown strength would be 300–400 V/µ in a reverse sandwich multilayer dielectric arrangement. The leakage current of the cell would be determined from appropriate DC testing. These high energy density dielectric capacitors are very different from electrochemical capacitors that utilize conducting polymers and liquid electrolytes and are constructed much like batteries. The dielectric capacitors have a very high cell voltage and are constructed like conventional ceramic capacitors.

Develop Single-Phase High Dielectric Constant SiO2-Based Composite Gate Dielectric

2010 ◽  
Vol 434-435 ◽  
pp. 259-262
Author(s):  
Chao Chin Chan ◽  
Yin Fang Wei ◽  
Chien Chen Diao ◽  
Yuan Tai Hsieh ◽  
Ping Shou Cheng
Keyword(s):  
Single Phase ◽  
High Dielectric Constant ◽  
Gate Dielectric ◽  
Raw Materials ◽  
Ceramic Materials ◽  
Dielectric Constants ◽  
Dielectric Characteristics ◽  
X Ray ◽  
High Dielectric ◽  
Ray Patterns

In this study, we hoped to find the single-phase high dielectric FET gate-used ceramic materials, which will be used in the sputtering method and have the dielectric constants higher than those of SiO2 and Si3N4. TiO2, La2O3 and ZrO2 are mixed with SiO2 to format the (1-x) TiO2-x SiO2, (1-x) ZrO2-x SiO2 and (1-x) La2O3-x SiO2 compositions, where x is dependent on the different raw materials. The all compositions are calcined at 1100oC and sintered at 1400oC~ 1550oC for 2hrs, and the X-ray patterns are used to find the crystal phases of all sintered ceramics. Because of the existence of single-phase, the sintering and dielectric characteristics of 0.3 La2O3-0.7 SiO2 ceramic are further developed.

High Dielectric Constant and Variable Range Hopping in Bi2Sr2YCu2Oy

1997 ◽  
Vol 11 (16n17) ◽  
pp. 727-738 ◽  
Author(s):  
M. Chandra Sekhar ◽  
B. Gopala Krishna ◽  
M. Maheshkumar ◽  
S. V. Suryanarayana
Keyword(s):  
Dielectric Constant ◽  
Single Phase ◽  
High Dielectric Constant ◽  
Solid State Reaction Method ◽  
Variable Range Hopping ◽  
Conductivity Measurements ◽  
Variable Range ◽  
Temperature Range ◽  
High Dielectric ◽  
Very High

The sample Bi2Sr2YCu2O y prepared by solid state reaction method showed a single phase Bi-2212. DC resistivity measured in the temperature range 77.5–300 K showed M–I like transition. AC conductivity measurements were performed in the temperature range 80–473 K at different frequencies. The conduction is by Mott's Variable Range Hopping. Various parameters pertaining to the conduction process are evaluated. The value of dielectric constant ε increases with temperature and shows a very high value. For a given temperature the value is found to decrease with increase in frequency.

Electron microscopy studies of PZT ferroelectric film capacitor structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1364-1365
Author(s):  
V. Kaushik ◽  
P. Maniar ◽  
J. Olowolafe ◽  
R. Jones ◽  
A. Campbell ◽  
...  
Keyword(s):  
Electric Fields ◽  
Sol Gel ◽  
Ferroelectric Material ◽  
Dielectric Constants ◽  
Dielectric Films ◽  
Lead Zirconium Titanate ◽  
Si Substrate ◽  
Film Capacitor ◽  
Pzt Films ◽  
High Dielectric

Lead zirconium titanate films (Pb (Zr,Ti) O3 or PZT) are being considered for potential application as dielectric films in memory technology due to their high dielectric constants. PZT is a ferroelectric material which shows spontaneous polarizability, reversible under applied electric fields. We report herein some results of TEM studies on thin film capacitor structures containing PZT films with platinum-titanium electrodes.The wafers had a stacked structure consisting of PZT/Pt/Ti/SiO2/Si substrate as shown in Figure 1. Platinum acts as electrode material and titanium is used to overcome the problem of platinum adhesion to the oxide layer. The PZT (0/20/80) films were deposited using a sol-gel method and the structure was annealed at 650°C and 800°C for 30 min in an oxygen ambient. XTEM imaging was done at 200KV with the electron beam parallel to <110> zone axis of silicon.Figure 2 shows the PZT and Pt layers only, since the structure had a tendency to peel off at the Ti-Pt interface during TEM sample preparation.

Observations on the Growth of YBa2Cu3O7 Thin Films at Very High Laser Fluences

1995 ◽  
Vol 388 ◽  
Author(s):  
Rand R. Biggers. ◽  
M. Grant Norton ◽  
I. Maartense ◽  
T.L. Peterson ◽  
E. K. Moser ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
High Fluences ◽  
Laser Fluences ◽  
High Laser ◽  
High Laser Fluences ◽  
Very High

AbstractThe pulsed-laser deposition (PLD) technique utilizes one of the most energetic beams available to form thin films of the superconducting oxide YBa2Cu3O7 (YBCO). IN this study we examine the growth of YBCO at very high laser fluences (25 to 40 J/cm2); a more typical fluence for PLD would be nearer to 3 J/cm2. the use of high fluences leads to unique film microstructures which, in some cases, appear to be related to the correspondingly higher moveabilities of the adatoms. Films grown on vicinal substrates, using high laser fluences, exhibited well-defined elongated granular morphologies (with excellent transition temperature, Tc, and critical current density, Jc). Films grown on vicinal substrates using off-axis magnetron sputtering, plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD), or PLD at more typical laser fluences showed some similar morphologies, but less well-defined. Under certain growth conditions, using high laser fluences with (001) oriented substrates, the YBCO films can exhibit a mixture of a- and c-axis growth where both crystallographic orientations nucleate on the substrate surface at the same time, and grow in concert. the ratio of a-axis oriented to c-axis oriented grains is strongly affected by the pulse repetition rate of the laser.

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