Dielectric properties of plasma-spray-deposited BaTiO3 and Ba0.68Sr0.32TiO3 thick films

2003 ◽  
Vol 18 (5) ◽  
pp. 1227-1231 ◽  
Author(s):  
K. Ahn ◽  
B. W. Wessels ◽  
S. Sampath
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Plasma Spray ◽  
Interfacial Layer ◽  
Thick Films ◽  
Low Dielectric Constant ◽  
Second Phase ◽  
Spray Process ◽  
Low Dielectric ◽  
Deposited Films

The dielectric properties of high-k dielectric BaTiO3 and Ba0.68Sr0.32TiO3 thick films deposited on alumina substrates using a plasma-spray process were investigated. The as-deposited films were predominantly crystalline but contained an amorphous second phase, the amount of which depended on spray conditions. The effect of the spray conditions on crystallinity was studied and related to the dielectric properties of the films. The presence of a low dielectric constant interfacial layer in plasma-spray-deposited films was determined from the dependence of the dielectric constant on film thickness. After annealing at 500 °C for 20 h in air, the crystallinity and dielectric constant increased. Annealing was also found to affect the interfacial layer properties.

Dielectric Properties of Spray Deposited BaTiO3 and Ba0.68Sr0.32TiO3

2001 ◽  
Vol 698 ◽  
Author(s):  
Kipyung Ahn ◽  
Bruce W. Wessels ◽  
Robert Greenlaw ◽  
Sanjay Sampath
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Dielectric Constants ◽  
Second Phase ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Hvof Spray ◽  
Deposited Films

ABSTRACTThe microstructure and dielectric properties of BaTiO3 and Ba0.68Sr0.32TiO3 thick films deposited by thermal spray were investigated. The as-deposited films were predominantly crystalline with a small amount of an amorphous second phase. The as-deposited BaTiO3 films had dielectric constants as high as 240 at room temperature. Upon annealing in air at 500°C, the dielectric constant increased to 480. This increase in dielectric constant was attributed, in part, to the crystallization of the amorphous second phase. The stabilized phase depended on the spray process used. The high velocity oxy fuel (HVOF) spray process resulted in the deposition of paraelectric BaTiO3, whereas the plasma spray process resulted in the ferroelectric phase.

scholarly journals Microwave dielectric properties of Na+-substituted CaMg0.9Li0.2Si2O6 ceramics

2022 ◽  
Vol 355 ◽  
pp. 01024
Author(s):  
Fangyi Huang ◽  
Hua Su ◽  
Xiaoli Tang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bulk Density ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Low Dielectric Constant ◽  
Second Phase ◽  
Experimental Sample ◽  
Low Dielectric ◽  
Microwave Dielectric

Ceramics with low dielectric constant are widely used in high frequency substrates. The low temperature sintered CaMg0.9-xNa2xLi0.2Si2O6(x = 0–0.05 and 0.1) ceramics with low dielectric constant and dielectric loss were prepared by the traditional solid-state reaction method, with 0.5wt%LBSCA additive. The XRD patterns of the samples were obtained by X-ray diffraction and it was found that there were three ceramic components, CaMgSi2O6, CaSiO3 and Na2MgSiO4, which indicated that the experimental sample was a multiphase ceramic system. Through the trend of bulk density as functions of the content of substitution and the change of SEM morphology, it could be found that appropriate amount of Na+ substitution can promote the grain growing and the densification of ceramics. Results demonstrated that both the Q × f and εr were relevant to bulk density and the second phase. The τf was also affected by the second phase to some extent. In particular, the ceramics sintered at 925 °C for 3h possessed the desirable microwave dielectric properties for LTCC application: εr = 7.03, Q × f = 17,956 GHz, and τf= −79 ppm/°C.

Novel soluble polyimides containing pyridine and fluorinated units: preparation, characterization, and optical and dielectric properties

RSC Advances ◽  
2016 ◽  
Vol 6 (26) ◽  
pp. 21662-21671 ◽  
Author(s):  
Weibing Dong ◽  
Yue Guan ◽  
Dejing Shang
Keyword(s):  
Dielectric Constant ◽  
Thermal Properties ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
Mechanical And Thermal Properties ◽  
Polyimide Films ◽  
Low Dielectric

To acquire low dielectric constant polyimide films with good mechanical and thermal properties and low CTE applied in microelectronic fields, three novel polyimides containing pyridine and –C(CF3)2– groups were firstly designed and synthesized.

Preparation and Properties of Porous Si3N4/SiO2/BN Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 828-831 ◽  
Author(s):  
Wei Dong ◽  
Chang An Wang ◽  
Lei Yu ◽  
Shi Xi Ouyang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
High Strength ◽  
Low Dielectric Constant ◽  
Pressureless Sintering ◽  
Composite Ceramics ◽  
Porous Si ◽  
Low Dielectric ◽  
Dry Pressing ◽  
Porous Si3n4

Porous Si3N4/SiO2/BN composite ceramics with high strength and low dielectric constant were prepared by dry-pressing process and pressureless sintering at 1750°C for 1.5 h in flow nitrogen. The influences of BN content on microstructure, porosity, mechanical and dielectric properties of the porous Si3N4/SiO2/BN composite ceramics were discussed. The results showed that the porous Si3N4/SiO2/BN composite ceramics with porosity ranging from 29% to 48% were fabricated by adjusting the content of BN. The flexural strength of the porous Si3N4/SiO2/BN composite ceramics was 78215 MPa. The dielectric constant of the porous Si3N4/SiO2/BN composite ceramics was 3.9~5 at 1 MHz.

Photosensitive Polyimide having low loss tangent for RF application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000476-000482 ◽  
Author(s):  
Masao Tomikawa ◽  
Hitoshi Araki ◽  
Yohei Kiuchi ◽  
Akira Shimada
Keyword(s):  
Molecular Structure ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
High Frequency ◽  
Low Dielectric Constant ◽  
Low Loss ◽  
Elongation At Break ◽  
Low Dielectric ◽  
The Poor

Abstract Progress of 5G telecommunication and mm radar for autopilot, high frequency operation is required. Insulator materials having low loss at high frequency is desired for the applications. We designed the low dielectric constant, and low dielectric loss materials examined molecular structure of the polyimide and found that permittivity 2.6 at 20GHz, dielectric loss 0.002. Furthermore, in consideration of mechanical properties such as the toughness and adhesion to copper from a point of practical use. Dielectric properties largely turned worse when giving photosensitivity. To overcome the poor dielectric properties, we designed the photosensitive system. After all, we successfully obtained 3.5 of dielectric constant and 0.004 of dielectric loss, and 100% of elongation at break. In addition, we offered a B stage sheet as well as varnish. These materials are applicable to re-distribution layer of FO-WLP, Interposer and other RF applications for microelectronics.

Dielectric Properties of Sol - Gel Silica Glasses

1986 ◽  
Vol 72 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Elemental Carbon ◽  
Sol Gel ◽  
Fused Silica ◽  
Dielectric Constants ◽  
Low Dielectric Constant ◽  
Silica Glasses ◽  
Low Dielectric ◽  
Gel Technique

AbstractDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (˜2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.

Bismaleimide/Allylnadic-Imide Blends Yield Low Dielectric Constant And Low Water Uptake

1991 ◽  
Vol 227 ◽  
Author(s):  
J-PH Ansermet ◽  
A. Kramer
Keyword(s):  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Water Uptake ◽  
Water Saturation ◽  
Low Dielectric Constant ◽  
Aliphatic Chain ◽  
Bismaleimide Resin ◽  
Low Dielectric

ABSTRACTThe bismaleimide resin Matrimid 5292A (I) was cocured with an allylnadic-imide resin (EP 433) which contained a long aliphatic chain as backbone (II). Water uptake, swelling, and the dielectric properties (up to 300 MHz) were studied in cast plates. The dielectric constant varied from 5.4 in (I) to 3.2 in (II) at water saturation, compared to 3.1 in (I) to 2.7 in (II) in the dry state. The glass transition temperature stayed above 200 °C at less than 80 mol% of (II).

Dielectric Properties of MgAl2O4 Transparent Nano-Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 412-413 ◽  
Author(s):  
Jie Zhang ◽  
Deng Xue Wu ◽  
Xiang Hui Chang ◽  
Tie Cheng Lu ◽  
Yi Hang Jiang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
Frequency Range ◽  
Low Dielectric

Dielectric constant and dielectric dissipation of MgAl2O4 transparent nano-ceramics were measured at different frequencies. The results indicated that the transparent nano-ceramic has a very low dielectric constant and low dielectric dissipation in frequency range of 1K~9MHz, but the dissipation of is independent of frequency. The dielectric constant of the transparent nano-ceramic does not vary signifycantly with temperature.

Influence of MgO Content on Microstructure and Dielectric Properties in (BaSr)TiO3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 85-88
Author(s):  
Lin Hu ◽  
He Ping Zhou ◽  
Hao Xue ◽  
Chun Lai Xu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Low Dielectric Constant ◽  
Microwave Technology ◽  
Phased Array Antennas ◽  
Strontium Titanium Oxide ◽  
Low Dielectric ◽  
Barium Strontium ◽  
High Dielectric

Barium strontium titanium oxide (BSTO) has great advantages and potentiality for the application of microwave technology. In order to be used in phased array antennas, high dielectric tunability, relatively low dielectric constant and low dielectric loss are required. In this paper, MgO was mixed into BSTO and the microstructure and dielectric properties of MgO-mixed BSTO bulk ceramics were investigated. The mole ratio of Ba and Sr was rather fixed to 5:5 in this study. It is observed that a small amount of MgO (5 wt%) has gone beyond the solubility limits of Mg in BSTO. The dielectric constant and dielectric loss of BSTO ceramics decreased with the increase of the content of MgO mixed. However, the tunability of MgO-mixed BSTO ceramics decreased at the same time. 20wt% MgO-mixed BSTO ceramics exhibits preferable dielectric properties with acceptable tunability.

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