Polymorphic Phase Transition and Temperature Coefficient of Capacitance of Alkaline Niobate Based Ceramics

배선기,신혜경,손은영,임인호 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.2

0.95(Na0.5K0.5)NbO3-0.05BaTiO3 + 0.2wt% Ag2O (hereafter, No excess NKN) ceramics and 0.95(Na0.5K0.5)NbO3-0.05BaTiO3 + 0.2wt% Ag2O with excess (Na0.5K0.5)NbO3 (hereafter, Excess NKN) were fabricated by the conventional solid state sintering method, and their phase transition properties and dielectric properties were investigated. The crystalline structure of No excess NKN ceramics and Excess NKN ceramics were shown characteristics of polymorphic phase transition (hereafter, PPT), especially shift from the orthorhombic to tetragonal phase by increasing sintering temperature range from 1,100℃ to 1,200℃. Also, the temperature coefficient of capacitance (hereafter, TCC) of No excess NKN ceramics and Excess NKN ceramics from -40℃ to 100℃ was measured to evaluate temperature stability for applications in cold regions. The TCC of No excess NKN and Excess NKN ceramics showed positive TCC characteristics at a temperature range from -40℃ to 100℃. Especially, Excess NKN showed a smaller TCC gradient than those of Excess NKN ceramics in range from -40℃ to 100℃. Therefore, NKN piezoelectric ceramics combined with temperature compensated capacitor having negative temperature characteristics is desired for usage in cold regions.

Polymorphic Phase Transition and Temperature Coefficient of Capacitance of Alkaline Niobate Based Ceramics

Bae, Seon-Gi,Shin, Hyea-Gyiung,Sohn, Eun-Young,Im, In-Ho The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.2

$0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3+0.2wt%\;Ag_2O$ (hereafter, No excess NKN) ceramics and $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3+0.2wt%\;Ag_2O$ with excess $(Na_{0.5}K_{0.5})NbO_3$ (hereafter, Excess NKN) were fabricated by the conventional solid state sintering method, and their phase transition properties and dielectric properties were investigated. The crystalline structure of No excess NKN ceramics and Excess NKN ceramics were shown characteristics of polymorphic phase transition (hereafter, PPT), especially shift from the orthorhombic to tetragonal phase by increasing sintering temperature range from $1,100^{\circ}C$ to $1,200^{\circ}C$. Also, the temperature coefficient of capacitance (hereafter, TCC) of No excess NKN ceramics and Excess NKN ceramics from $-40^{\circ}C$ to $100^{\circ}C$ was measured to evaluate temperature stability for applications in cold regions. The TCC of No excess NKN and Excess NKN ceramics showed positive TCC characteristics at a temperature range from $-40^{\circ}C$ to $100^{\circ}C$. Especially, Excess NKN showed a smaller TCC gradient than those of Excess NKN ceramics in range from $-40^{\circ}C$ to $100^{\circ}C$. Therefore, NKN piezoelectric ceramics combined with temperature compensated capacitor having negative temperature characteristics is desired for usage in cold regions.

Metal-Insulator-Metal 캐패시터의 응용을 위한 비정질 BaTi₄O₉ 박막의 전기적 특성

홍경표,정영훈,남산,이확주,Hong, Kyoung-Pyo,Jeong, Young-Hun,Nahm, Sahn,Lee, Hwack-Joo 한국재료학회 2007 한국재료학회지 Vol.17 No.11

Amorphous $BaTi_4O_9$ ($BT_4$) film was deposited on Pt/Si substrate by RF magnetron sputter and their dielectric properties and electrical properties are investigated. A cross sectional SEM image and AFM image of the surface of the amorphous $BT_4$ film deposited at room temperature showed the film was grown well on the substrate. The amorphous $BT_4$ film had a large dielectric constant of 32, which is similar to that of the crystalline $BT_4$ film. The leakage current density of the $BT_4$ film was low and a Poole-Frenkel emission was suggested as the leakage current mechanism. A positive quadratic voltage coefficient of capacitance (VCC) was obtained for the $BT_4$ film with a thickness of <70 nm and it could be due to the free carrier relaxation. However, a negative quadratic VCC was obtained for the films with a thickness ${\geq}96nm$, possibly due to the dipolar relaxation. The 55 nm-thick $BT_4$ film had a high capacitance density of $5.1fF/{\mu}m^2$ with a low leakage current density of $11.6nA/cm^2$ at 2 V. Its quadratic and linear VCCs were $244ppm/V^2$ and -52 ppm/V, respectively, with a low temperature coefficient of capacitance of $961ppm/^{\circ}C$ at 100 kHz. These results confirmed the potential suitability of the amorphous $BT_4$ film for use as a high performance metal-insulator-metal (MIM) capacitor.

Crystalline Phases and Dielectric Properties of Crystallized Glasses in the System (Ca, Sr, Ba) O-Al2O3-B2O3-SiO2-TiO2

Tuzuku, Koichiro,Kishi, Hiroshi,Taruta, Seiichi,Takusagawa, Nobuo The Korean Ceramic Society 1999 The Korean journal of ceramics Vol.5 No.2

Crystallization of glasses in the system (Ca, Sr, Ba)$O-Al_2O_3-B_2O_3-SiO_2-TiO_2$ and dielectric properties of crystallized glasses were investigated. As increasing B2O3 content and decreasing SiO2 content in the glass, the major crystalline phase changed from $(Sr, Ba)_2TiSi_2O_8$ to (Ca, Sr, Ba)TiO3, the dielectric constant of crystallized glasses increased and the Temperature Coefficient of Capacitance (TCC) changed to negative. The dielectric constant and TCC was estimated for (Sr, Ba)2TiSi2O8 phase as 18 and -440 $ppm/^{\circ}C$, respectively and for (Ca, Sr, Ba)TiO3 phase as 307 and -1900 $ppm/^{\circ}C$, respectively. The dielectric properties of (Ca, Sr, Ba)TiO3 phase (in this study) were similar to those of (Ca, Ba) TiO_3 solid-solution^12)$</TEXX>, but $(Sr, Ba)_2TiSi_2O_8$ phase (in this study) and $Sr_2TiSi_2O_\;8^4$ showed the different properties.

고압용 X7R 적층 칩 캐패시터의 Er₂O₃ 및 유리프릿 첨가에 따른 전기적 특성

윤중락,김민기,정태석,우병철,이석원,Yoon, Jung-Rag,Kim, Min-Kee,Chung, Tae-Seog,Woo, Byoung-Chul,Lee, Seog-Won 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.5

To manufacture the MLCC with X7R for high voltage stability, $BaTiO_3-MgO-MnO_2-Y_2O_3$ with $(Ba_{0.4}Ca_{0.6})SiO_3$ glass frit was formulated. Based on this composition, the addition of $Er_2O_3$ showed that TCC(Temperature Coefficient Capacitance) at $85^{\circ}C$ was improved from 5 % to ${\sim}0\;%$, but the dielectric constant and IR (Insulation Resistance) were decreased. The glass frit improved the dielectric constant and IR, so the appropriate contents of $Er_2O_3$ and glass frit were 0.6 mol% and 1 wt%, respectively. It showed that the dielectric constant and RC constant were 2,550 and 2,000 (${\Omega}F$), respectively in the sintering condition at $1250^{\circ}C$ in PO2 $10^{-7}$ Mpa. The MLCC with $3.2{\times}1.6$ (mm) size and $1\;{\mu}F$ was also suited for X7R with the above composition.

금속유기분해법을 사용한 Zr0.7Sn0.3TiO4 박막 제조 및 유전특성

선호정 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.4

Zr0.7Sn0.3TiO4 (ZST) thin films were fabricated by metal-organic decomposition, and their dielectric properties were investigated in order to evaluate their potential use in passive capacitors for rf and analog/mixed signal integrated circuits. The ZST thin film annealed at the temperature of 800℃ showed a dielectric constant of 27.3 and a dielectric loss of 0.011. The capacitor using the ZST film had quadratic and linear voltage coefficient of capacitance (VCC) of -65 ppm/V2 and -35 ppm/V at 100 kHz, respectively. It also exhibited a good temperature coefficient of capacitance (TCC) value of -32 ppm/℃ at 100 kHz.

Pb(Mg1/3Nb2/3)O3-PbTiO3계의 조성변화에 의한 다층 콘덴서 물성

김복희 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.2

Multilayer ceramic capacitors(MLCC) were prepared by laminating the layer of composition with dif-ferent Curie temperature to improve temperature coefficient in the Pb(Mg1/3Nb2/3)O3-PbTiO3 binary system. Green sheet was formed by tape casting using Pb(Mg1/3Nb2/3)O3-PbTiO3 and PbTiO3 synthesized with solid state reaction of PBO. Nb2O5 MgO and TiO2. Green sheet with electrode of 70Ag-30Pd was laminated under 300 kg/cm2 at 70$^{\circ}C$ and sintered at 1100$^{\circ}C$ for 2hr. Curie temperatues for MLCC with 10 layers of pure PMN and 0.9PMN-0.1PT were lowered to -22$^{\circ}C$ and 36$^{\circ}C$ respectively. MLCC with 7 layers of PMN and 3 layers of 0.9PMN-0.1PT showed nearly zero temperature coefficient of capacitance in the range of -20∼30$^{\circ}C$ and sum of dissipation factor of each layer.

$CaTiO_3$ 유전 재료의 소결온도와 조성변화에 따른 물리적 및 전기적 특성 변화

우성수,안영수,한문희,노광수 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.10

To use dielectric material of high power multilayer capacitor, the composition of the commercial CaTiO3 was changed to decrease the sintering temperature, and the physical and electrical properties were investigated. Series of experiments showed that CaTiO3 with sintering additives had the highest density, the highest shrinkage, the lowest dielectric constant, the lowest loss factor, and the lowest temperature coefficient of capacitance (TCC). These properties had the constant values at sintering temperature of above 120$0^{\circ}C$.

Yttrium이 첨가된 BaTiO₃에서 형성된 core/shell 구조에서 shell의 TCC 거동: 독립적 관찰

전상채,Jeon, Sang-Chae 한국결정성장학회 2020 한국결정성장학회지 Vol.30 No.3

MLCC(Multi-Layer Ceramic Capacitor)의 유전체 층에 사용되는 BaTiO₃ 입자는 안정한 TCC(Temperature Characteristics of Capacitance) 거동을 갖기 위해 core/shell 구조를 갖는다. 지금까지 shell의 특성은 core/shell 구조의 전체 특성에서 유추해 왔다. 이는 core/shell 구조가 겨우 수 ㎛의 작은 크기로 shell 특성만 구별해서 측정하기가 어렵기 때문이다. 본 실험에서는 micro-contact법을 이용하여 확산쌍 시편의 계면에 형성된 확대된 core/shell 구조에 Pt 전극을 증착하여 35~135℃ 에서 shell 영역의 독립적인 TCC 거동을 측정하였다. 그 결과, 65℃에서 최대 유전율 값을 갖는 완만한 피크의 확산 상전이(Diffusion Phase Transition) 거동인 core의 특성과 구별되는 거동을 관찰하였으며, 이는 core/shell 구조의 온도-유전거동을 묘사하는 모델링에서 실험 자료로 활용될 것으로 본다. Grains in the BaTiO₃, which is used for a dielectric layer in MLCC(Multi-Layer Ceramic Capacitor) are necessary to form core/shell structure for a stable TCC(Temperature Coefficient of Capacitance) behavior. The shell property has been deduced from the whole TCC behavior of core/shell structure due to its tiny size, ~ few ㎛. This study demonstrates the individual TCC behavior of the shell phase measured by micro-contact measurement in a temperature range between 35 and 135℃. Pt electrode pairs deposited on an enlarged core/shell structure in a diffusion couple sample made the measurement possible. As a result, the DPT (Diffusion Phase Transition) behavior of the shell phase was revealed as a different TCC behavior from that of the core: a broad peak with T_m at 65℃. This would be also useful experimental data for a modelling that depicts dielectric-temperature behavior of core/shell structure.

Dielectric properties of (Ca0.7Sr0.3)(Zr0.97Ti0.03)O3-(Li0.5Nd0.5)TiO3 ceramics

Seung-Hwan Lee,Min-Kee Kim,Hong-Ki Kim,Jung Rag Yoon 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.10

The dielectric properties of the (1-x)(Ca0.7Sr0.3)(Zr0.97Ti0.03)O3-x(Li0.5Nd0.5)TiO3 ceramics were studied. The permittivity improved from 35 to 67 and quality factor decreased continuously from 10,000 to 800 with an increase in (Li0.5Nd0.5)TiO3 content in the (1-x)(Ca0.7Sr0.3)(Zr0.97Ti0.03)O3-x(Li0.5Nd0.5)TiO3 compositions. The crystal structures of (1-x)(Ca0.7Sr0.3) (Zr0.97Ti0.03)O3-x(Li0.5Nd0.5)TiO3ceramics were confirmed to be perovskite with an orthorhombic crystal system. The increase in the dielectric constant and temperature coefficient capacitance with the increase in (Li0.5Nd0.5)TiO3 content could be explained by mixture rule. Obviously, (Li0.5Nd0.5)TiO3 content could efficiently improve the dielectric properties for temperature stabilized multilayer ceramic capacitor with high energy density.