Effect of re-oxidation on dielectric properties in Ni-MLCC

Kishi, Hiroshi; Mizuno, Youichi; Hagiwara, Tomoya; Orimo, Hirokazu; Ohsato, Hitoshi

doi:10.1007/s10832-007-9072-z

Cited by 9 publications

(5 citation statements)

References 14 publications

(15 reference statements)

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“…These requirements naturally call for the use of two‐step sintering, but the compositional and microstructural complexity of MLCC BaTiO 3 may present a challenge. Such complexity is partially necessitated by the technology: MLCC is co‐fired with base metal inner electrodes (Ni or Cu) at a relatively low temperature in a reducing atmosphere (sometimes followed by a short reoxidation treatment). To practice the above without risking resistivity loss, various donor and acceptor dopants as well as amphoteric trivalent rare‐earth dopants (Y, Ho and Dy) have been introduced to ameliorate the effect of reducing atmosphere (and the subsequent reoxidation atmosphere if necessary).…”

Section: Introductionmentioning

confidence: 99%

Superior Reliability Via Two‐Step Sintering: Barium Titanate Ceramics

et al. 2015

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Two‐step sintering (TSS) in a reducing atmosphere has been employed to obtain fine‐grain BaTiO3 ceramics with a core‐shell microstructure, a more uniform grain‐size distribution, and superior reliability for multilayer ceramic capacitor applications. Compared to ceramics of the same composition conventionally sintered for about the same time, TSS ceramics feature a thinner shell thickness thus a stronger dopant localization, which leads to a lower VnormalO∙∙ concentration, higher internal resistance and more dopant‐VnormalO∙∙ association. Improved reliability is manifest in a 50% higher breakdown strength at ambient temperature and a 400% longer endurance time to withstand DC stress at 185°C, in addition to a less field‐and‐temperature‐dependent capacitance. A scaling analysis of the VnormalO∙∙ redistribution and endurance dynamics identifies VnormalO∙∙ transmission across the shell‐grain‐boundary region as the critical element beneficially impacted by core‐shell structure and two‐step sintering.

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Section: Introductionmentioning

confidence: 99%

Superior Reliability Via Two‐Step Sintering: Barium Titanate Ceramics

et al. 2015

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“…Its dissipation factor is higher at low temperature than that of other samples. For such a difference in dielectric-temperature behavior among samples, several causes have been proposed, including differences in (a) the concentration of dopants in the shell [19,34], (b) the occupational site of rare-earth elements in the shell [16][17][18]35], (c) charge carrier concentrations and the resultant valence state of Ti [27,28], and (d) the residual strain [24,36]. In this study, the effect of the concentration of dopants can be excluded because all the samples were prepared under the same experimental conditions, except the oxidation temperature, which should not affect the distribution of dopants in the shell.…”

Section: Resultsmentioning

confidence: 99%

“…Many studies have tried to elucidate the effects of oxygen vacancies on the dielectric relaxation [10,11], the resistance degradation [3,7,[12][13][14][15], and the occupational site of rareearth elements in BaTiO 3 [16][17][18]. On the other hand, few studies have reported the effect of oxygen vacancies on the microstructure and dielectric-temperature behavior in core/shell structured BaTiO 3 .…”

Section: Introductionmentioning

confidence: 99%

Oxidation-induced strain relaxation and related dielectric-temperature behavior in core/shell grained BaTiO3

Jeon

Kang

2015

J Electroceram

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The effect of oxidation on dielectric-temperature behavior of core/shell grained BaTiO 3 was studied in an attempt to reveal the prime governing parameter of dielectrictemperature behavior. BaTiO 3 samples doped with 3 mol% Y 2 O 3 or 3 mol% Dy 2 O 3 with the same effective charges were sintered in a reducing atmosphere (Po 2 <10 −13 ) and oxidized at 1050-1250°C for 10 h in air. In the Y-doped samples, as the oxidation temperature increased, the fraction of the grains with ferroelectric domains in the shell increased from 18 to 54 % and the residual strain decreased. With an increased domain fraction, the dielectric-temperature behavior became poor, and a dielectric peak appeared. On the other hand, all the Dy-doped and air-annealed samples exhibited relatively high fractions of grains with ferroelectric domains in the shell, 32 % at 1050°C and 63 % at 1250°C, indicating a considerable reduction of residual strain in all the samples. The temperature stability of the Dy-doped samples was poor, and there was a dielectric peak, irrespective of the oxidation temperature. This difference in dielectric response between the Ydoped and Dy-doped samples reveals that the prime factor governing the dielectric-temperature stability is the residual strain in the core/shell grains rather than the previously suggested factors of defect concentration, dopant concentration in the shell and the occupational sites of rare-earth dopants.

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“…9(b)], probably owing to the applied voltage of as low as 100 mV. To overcome the negative impact of charge trapping, post-annealing in oxygen atmosphere will be effective to reoxidize the vacancy sites, 48) as well as the complete aging of the precursor gel films followed by their crystallization in air. 44,45) Furthermore, the polar-axis orientation, i.e., the alignment of BaTiO 3 (001) to the substrate surface, would contribute significantly to the enhancement of polarization behavior by applying thermal stress during the crystallization process, 30,31,36,37) although the resulting films in the present research exhibited a nonpolar-axis orientation of BaTiO 3 (100).…”

Section: Processing In Vacuummentioning

confidence: 99%

Orientation control of barium titanate films using metal oxide nanosheet layer

Uchida

Noguchi

et al. 2016

Jpn. J. Appl. Phys.

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In the present work, we aim to achieve the preferred crystal orientation of chemical solution deposition (CSD)-derived BaTiO3 films on ubiquitous Si wafers with the assistance of Ca2Nb3O10 nanosheet (ns-CN) template layers. The ns-CN on platinized Si (Pt/Si) substrates aligned the BaTiO3(100) plane to the substrate surface, because of the favorable lattice matching of the ns-CN (001) plane. The CSD process in air required a high crystallization temperature of 900 °C for the preferred crystal orientation of BaTiO3(100) because of the BaCO3 byproduct generated during the combustion reaction of the precursor gel. The processing in vacuum to remove CO2 species enhanced the crystal orientation even at the crystallization temperature of 800 °C, although it can generate oxygen vacancies ( ) that cause distorted polarization behavior under an applied field higher than approximately 150 kV/cm. The relative dielectric constant (εr) of the (100)-oriented BaTiO3 film on the ns-CN-supported Pt/Si substrate (ns-CN/Pt/Si) was generally larger than that of the randomly oriented film on Pt/Si, depending on the degree of crystal orientation.

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Effect of re-oxidation on dielectric properties in Ni-MLCC

Cited by 9 publications

References 14 publications

Superior Reliability Via Two‐Step Sintering: Barium Titanate Ceramics

Superior Reliability Via Two‐Step Sintering: Barium Titanate Ceramics

Oxidation-induced strain relaxation and related dielectric-temperature behavior in core/shell grained BaTiO3

Orientation control of barium titanate films using metal oxide nanosheet layer

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