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.

CuO 첨가에 따른 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 세라믹스의 유전 이완 특성

배선기,임인호,신혜경,이석진 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.2

We investigated the dielectric relaxation properties 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with CuOaddition. With increasing CuO addition, the lattice parameter was increased by substitution of small amount Cu2+ion in B-site of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics. Also the grain size and the maximum dielectricconstant of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics was decreased with increasing amounts of CuO addition. Moreover, the diffused phase transition properties (γ) of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics wasincreased by compositional fluctuation with increasing of CuO amount, changed from 1.45 at 1 wt% CuO additionto 1.94 at 7 wt% CuO addition. 본 연구에서는 CuO 첨가에 따른 Ba(Zr,Ti)O3 -(Ba,Ca)TiO3 세라믹스의 결정구조 변화, 미세구조 변화 및 유전 이완 특성을 조사하였다. BZT-BCT 세라믹스에 CuO 첨가량에 관계없이 결정구조는 능면제정계 구조를 나타내었다. 그러나 CuO 첨가량이 증가함에 따라 Cu2+ ion의 B-site 치환효과에 의해 격자상수가 증가하는 경향을 나타내었다. 또한 CuO가 소결시 소결 조제로서 역할함에 따라 결정립의 치밀화가 촉진되어 결정립 크기와 최대 유전상수는 경향을 나타내었다. 특히, CuO 첨가량이 증가함에 따라 BZT-BCT 세라믹스는 전형적인 확산형 상전이 특성을 나타내었으며, 확산정수 γ 값은 CuO 1 wt% 첨가 시 1.45에서 CuO 7 wt% 첨가시 1.94로 증가하였다.

CuO 첨가에 따른 0.5Ba(Zr_0.2Ti_0.8)O₃-0.5(Ba_0.7Ca_0.3)TiO₃ 세라믹스의 유전 이완 특성

배선기,신혜경,이석진,임인호,Bae, Seon Gi,Shin, Hyea-Kyoung,Lee, Suk-Jin,Im, In-Ho 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.2

We investigated the dielectric relaxation properties $0.5Ba(Zr_{0.2}Ti_{0.8})O_3-0.5(Ba_{0.7}Ca_{0.3})TiO_3$ ceramics with CuO addition. With increasing CuO addition, the lattice parameter was increased by substitution of small amount $Cu^{2+}$ ion in B-site of $0.5Ba(Zr_{0.2}Ti_{0.8})O_3-0.5(Ba_{0.7}Ca_{0.3})TiO_3$ ceramics. Also the grain size and the maximum dielectric constant of $0.5Ba(Zr_{0.2}Ti_{0.8})O_3-0.5(Ba_{0.7}Ca_{0.3})TiO_3$ ceramics was decreased with increasing amounts of CuO addition. Moreover, the diffused phase transition properties (${\gamma}$) of $0.5Ba(Zr_{0.2}Ti_{0.8})O_3-0.5(Ba_{0.7}Ca_{0.3})TiO_3$ ceramics was increased by compositional fluctuation with increasing of CuO amount, changed from 1.45 at 1 wt% CuO addition to 1.94 at 7 wt% CuO addition.

(Ba,Ca)SiO₃ Glass Frit 첨가에 따른 NKN-BT 세라믹스의 유전 완화 특성

배선기,신혜경,이승환,임인호,Bae, Seon Gi,Shin, Hyeo-Kyung,Lee, Seung-Hwan,Im, In-Ho 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.6

We investigated dielectric relaxation properties of $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ ceramics by addition (0~0.3 wt%) of $(Ba,Ca)SiO_3$ glass frit. All composition of $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ added $(Ba,Ca)SiO_3$ glass frit showed the same crystallographic properties, coexistence of orthorhombic and tetragonal phase. By increasing addition of $(Ba,Ca)SiO_3$ glass frit, the Curie temperatures of $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ ceramics were decreased, whereas maximum dielectric constants of $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ ceramics were dramatically increased. Especially the deviations of Curie temperature $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ ceramics were increased by increasing amount of $(Ba,Ca)SiO_3$ glass frit, and it indicated that $0.95(Na_{0.5}K_{0.5})NbO_3-0.05BaTiO_3$ ceramics added $(Ba,Ca)SiO_3$ glass frit have relaxor characteristics.

Effect of Particle Size on the Dielectric and Piezoelectric Properties of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 Lead-free Piezoelectric Ceramics

배선기,류주현,신혜경,정광현,임인호 한국전기전자재료학회 2015 Transactions on Electrical and Electronic Material Vol.16 No.4

The particle sizes of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 powder were controlled by secondary milling time after calcination. The average particle sizes, Dmean, of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 powders were critically changed from 14.31 μm to 0.91 μm by secondary milling time. The dielectric and piezoelectric properties of 0.95(K0.5Na0.5)NbO3- 0.05BaTiO3 ceramics depended on the particle sizes of powders after calcination and the secondary milling process. As secondary milling times after calcination were increased to more than 48 hr, the dielectric and piezoelectric properties of 0.95(K0.5Na0.5)NbO3-0.05BaTiO3 ceramics were deteriorated.

CuO 첨가에 따른 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 세라믹스의 유전 이완 특성

배선기 ( Seon Gi Bae ),신혜경 ( Hyea Kyoung Shin ),이석진 ( Suk Jin Jin Lee ),임인호 ( In Ho Im ) 한국전기전자재료학회 2015 전기전자재료 Vol.28 No.2

We investigated the dielectric relaxation properties 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with CuO addition. With increasing CuO addition, the lattice parameter was increased by substitution of small amount Cu2+ion in B-site of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics. Also the grain size and the maximum dielectric constant of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics was decreased with increasing amounts of CuO addition. Moreover, the diffused phase transition properties (γ) of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics was increased by compositional fluctuation with increasing of CuO amount, changed from 1.45 at 1 wt% CuO addition to 1.94 at 7 wt% CuO addition.

MIM 샌드위치 구조의 전도메카니즘에 관한 연구

배선기,박창엽,남춘우 연세대학교 산업기술연구소 1984 논문집 Vol.16 No.1

In this study, the MIM devices of Al-Al₂O₃-Al, Al-Al₂O₃-Ag structure with junction area ??[㎠] and thickness of oxide layer 30[Å] were fabricated, and then those conduction mechanism and characteristics were investigated. The results, at low voltage region the voltage-current characteristics was ohmic because of the quantum mechanical tunneling and hopping process, and at high voltage region the voltage-current characteristics was I∝V² because of the space charge limited conduction. The voltage which transited from ohmic to I∝ V² and the barrier height were 110[mV], 0.42[eV] of Al-Al₂O₃-Al device and 90[mV], 0.44[eV] of Al-Al₂O₃-Ag device respectively. The polarity dependence of voltage-current characteristics was found only in Al-Al₂O₃-Ag device because of the intrinsic field in insulator thin film.

Pb(Zn<SUB>1/3</SUB>Nb<SUB>2/3</SUB>)O₃-BaTiO₃-PbTiO₃ 세라믹의 유전특성에 관한 연구

裵善基(Seon-Gi Bae),李成甲(Sung-Gap Lee),李永熙(Young-Hie Lee) 대한전기학회 1989 전기학회논문지 Vol.38 No.10

질환탄소 박막 증착 시 고전압 방전 플라즈마에 가한 자장의 영향

김종일,배선기 한국전기전자재료학회 2002 전기전자재료학회논문지 Vol.15 No.2

Carbon nitride films were grown on Si (100) substrate by a laser-electric discharge method with/without a magnetic field assistance. The magnetic field leads to vapor plume plasma expending upon the ambient arc discharge plasma area. Influence of the magnetic field has resulted in increased of a crystallite size int he films due to bombardment (heating) of Si substrates by energetic carbon and nitrogen species generated during cyclotron motion of electrons in the discharge zone. The surface morphology of the films with a deposition time of 2 hours was studied using a scanning electron microscopy (SEM). In order to determine the structural crystalline parameters, X-ray diffraction (XRD) was used to analysis the grown films.

표시소자 응용을 위한 copper, aluminum 박막의 성장과 특성

김형택,배선기 한국전기전자재료학회 1995 電氣電子材料學會誌 Vol.8 No.3

Electrical, physical and optical properties of Aluminum(Al), Copper(Cu) thin films were investigated in order to establish the optimum sputtering parameters in Liquid Crystal Display (LCD) panel applications. DC-magnetron sputtered film on coming 7059 samples were fabricated with variations of deposition power densities, deposition pressures and substrate temperatures. Low resistivity films(AI;2.80 .mu..ohm.-cm, Cu:1.84 .mu..ohm-cm),which lower than the reported values, were obtained under sputtering parameters of power density(250W), substrate temperature(450-530.deg. C) and 5*10$\^$-3/ Torr deposition pressure. Expected columnar growth and stable grain growth of both films was observed through the Scanning Electron Microscope(SEM) micrographs. Dependency of the applicable defect-free film density upon depositon power and temperature was also characterized. Not too noticable variations in X-ray diffraction patterns were remarked under the alterations of sputtering parameters. High optical reflectivities of Al, Cu films, approximately 70-90 %, showed high degree of surface flatness.