자기전기복합체의 비공진 및 공진 상태에서의 자기전기 결합 특성 평가 방법

파틸디팍,류정호 한국전기전자재료학회 2022 전기전자재료학회논문지 Vol.35 No.4

자기전기복합체(magnetoelectric, ME compositie)는 자왜재료와 압전재료의 결합현상을 이용하는 재료로서지난 20여 년간 이론적, 실험적으로 많은 연구가 진행되어 왔다. 자기전기복합체의 출력특성은 구성하는 소재, 계면층,복합체의 형상, 자기장하 진동모드 등의 많은 구성요소의 최적화를 통하여 급속히 향상되고 있다. 하지만 자기전기복합체의 자기전기 결합 특성 평가는 대부분의 연구들에서 구체적인 방법을 제시하지 않아 어떻게 측정한 것인지가 불명확한 경우가 많다. 본 논문에서는 자기전기복합체의 비공진, 공진상황에서 자기전기 전압계수를 어떻게 측정할 수 있는지에 대한 자세한 방법을 소개한다. 평가를 위한 샘플로서 대칭적인 구조를 가지는 Gelfenol/PMN-PZT/Gelfenol자기전기복합체를 제조하였다. 압전 재료로는 이방성의 (011) 32 모드의 PMN-PZT 압전 단결정과 자왜재료로는 Galfenol 합금을 사용하여 에폭시로 접착하였다. 컴퓨터 인터페이스로 자동화된 자기전기 전압특성 측정 시스템의 구성을 우선 설명하고, 자기전기 결합특성의 측정 방법을 단계별로 설명한다. 본 튜토리얼 논문에서는 자기전기결합 특성과 특성평가방법을 이해하고자 하는 연구자들에게 도움이 될 수 있는 평가방법의 원리와 절차를 제공하고자 하였다.

한국전기전자재료학회 뉴스

한국전기전자재료학회 한국전기전자재료학회 2022 전기전자재료 Vol.35 No.4

비-휘발성 저항 변화 메모리 응용을 위한 WOx 물질의 전기적 특성 연구

석중현,정균호,김경민,송승곤,박윤선,박경완 한국전기전자재료학회 2016 전기전자재료학회논문지 Vol.29 No.5

In this study, we observed current-voltage characteristics of the MIM (metal-insulator-metal) structure. The WOx material was used between metal electrodes as the oxide insulator. The structure of the Al/WOx/TiN shows bipolar resistive switching and the operating direction of the resistive switching is clockwise, which means set at negative voltage and reset at positive voltage. The set process from HRS (high resistance state) to LRS (low resistance state) occurred at . The reset process from LRS to HRS occurred at . The on/off current ratio was about and resistive switching was performed for 5 cycles in the endurance characteristics. With consecutive switching cycles, the stable and were observed. The electrical transport mechanism of the device was based on the migration of oxygen ions and the current-voltage curve is following (Ohm’s Law → Trap-Controlled Space Charge Limited Current → Ohm’s Law) process in the positive voltage region. 본 실험에서, 우리는 MIM(Metal-Insulator-Metal) 구조의 전류-전압 특성들을 관찰하였다. 금속 전극들 사이에 산화 절연체로서 WOx 물질을 사용하였다. Al/WOx/TiN의 구조는 양극성 저항 변화 스위칭을 보여주고 저항 변화 스위칭의 동작 방향은 음의 전압에서 set, 양의 전압에서 reset인 시계 방향이다. 높은 저항 상태에서 낮은 저항 상태로 변하는 set 과정은 –2.6 V에서 일어났다. 낮은 저항 상태에서 높은 저항 상태로 변하는 reset 과정은 2.78 V에서 일어났다. On/Off 전류비는 10이었고, 내구성 특성을 위해 5번 주기의 저항 변화 스위칭을 실행하였다. 연속전인 스위칭 주기에 따라 안정적인 Vset과 Vreset은 관찰되었다. 소자의 전기적인 수송 메커니즘은 산소 이온들의 이동을 기초로 하며 전류 전압 곡선은 양의 전압 영역에서 (옴의 법칙 → 공간 전하 제한 전류 → 옴의 법칙) 과정을 따른다.

H₂O₂ 산화제가 W/Ti 박막의 전기화학적 분극특성 및 CMP 성능에 미치는 영향

나은영,서용진,이우선,Na, Eun-Young,Seo, Yong-Jin,Lee, Woo-Sun 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.6

CMP(chemical mechanical polishing) process has been attracted as an essential technology of multi-level interconnection. Also CMP process got into key process for global planarization in the chip manufacturing process. In this study, potentiodynamic polarization was carried out to investigate the influences of $H_2O_2$ concentration and metal oxide formation through the passivation on tungsten and titanium. Fortunately, the electrochemical behaviors of tungsten and titanium are similar, an one may expect. As an experimental result, electrochemical corrosion of the $5\;vol\%\;H_2O_2$ concentration of tungsten and titanium films was higher than the other concentrations. According to the analysis, the oxidation state and microstructure of surface layer were strongly influenced by different oxidizer concentration. Moreover, the oxidation kinetics and resulting chemical state of oxide layer played critical roles in determining the overall CMP performance. Therefore, we conclude that the CMP characteristics tungsten and titanium metal layer including surface roughness were strongly dependent on the amounts of hydrogen peroxide oxidizer.

전극 형태와 전극 간 거리에 따른 전기적 특성 분석

김태희 ( Tae-hee Kim ),이순형 ( Soon-hyung Lee ),황미용 ( Mi-yong Hwang ),최용성 ( Yong-sung Choi ) 한국전기전자재료학회 2023 전기전자재료학회논문지 Vol.36 No.4

In this paper, in order to analyze high electrical insulation and cooling performance using mineral oil, the liquid insulating oil was changed in electrode shape and distance between electrodes to compare and analyze electrical characteristics according to equal electric field, quasi-equivalent electric field, and unequal electric field. As a result, the breakdown voltages were 36,875 V and 36,875 V in the form of sphere-sphere and plate-plate electrodes with equal electric fields. The breakdown voltage was 31,475 V in the sphere-plate electrode type, which is a quasi-equilibrium field, and the breakdown voltage was 28,592 V, 27,050 V, and 22,750 V in the needle-needle, sphere-needle, and needle-plate electrode types, which are unequal fields. Through this, it is possible to know the difference in breakdown voltage according to the type of electric field. The more equal the field, the higher the breakdown voltage, and the more unequal field, the lower the breakdown voltage. The difference in insulation breakdown voltage could be seen depending on the type of electric field, the insulation breakdown voltage was higher for the more equal electric field, and the insulation breakdown voltage was lower for the more unequal electric field. Also, it was confirmed that the closer the distance between the electrodes, the higher the insulation breakdown voltage, the higher the insulation breakdown current, and the insulation breakdown voltage and the insulation breakdown current were proportional.

전계가 가해진 절연유의 유동대전 특성 고찰

허창수,정중일 한국전기전자재료학회 1997 電氣電子材料學會誌 Vol.10 No.4

Streaming electrification on insulating paper and pressboard under D.C. and A.C. electric field was investigated by using paper tubes and oil circulation apparatus. At first, flowing of static charges as measured with no electric field. As the temperature of oil increased, the measured current curve hows peak. As the velocity increased, it shows increasing exponential curve. Then, we applied A.C. and D.C. electric field on paper tube and the current from relaxation tank to earth was measured, which other factors such as temperature and velocity were varied like case of no electric field. The ions in oil carry the charges. So electric field makes asymmetry effect, and electrophoretic effect on ions in oil. We find that as the electric field intensity increased, the charges which were made by electric double layer were increased. The charge vs. velocity curve made peak point at a velocity.

$e^-$-$CF_4$산란중에서 전자군의 확산계수 및 에너지분포함수 연구

하성철,임상원 한국전기전자재료학회 1997 電氣電子材料學會誌 Vol.10 No.4

In this paper, the behavior of electron swarm parameters and energy distribution function of the discharge under high E/N condition in e$^{-10}$ -CF$_{4}$ gas have been analysed over the E/N range from 1-300(Td) by the MCS and BEq methods using set of electron collision cross section determined by the authors. The swarm parameters and energy distribution function have been calculated for the pulsed Townsend, steady-state Townsend and Time of Flight methods. The results gained that the value of electron swarm parameters such as the electron drift velocity, the electron ionization and attachment coefficients and longitudinal diffusion coefficients in agreement with the experimental and theoretical data for a range of E/N. The electron energy distribution function has been explained and analysed in e$^{-10}$ -CF$_{4}$ at E/N : 5, 10, 100, 200, 300(Td) for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The validity of the results has been confirmed by TOF and SST methods.

배전 케이블의 절연체내 불순물이 전기전도도에 미치는 영향

이우선,김남오,정용호,최재곤,김형곤,김상준 한국전기전자재료학회 1997 電氣電子材料學會誌 Vol.10 No.5

Effects of metal impurities in insulation of distribution cables on electrical conduction of distribution cables was investigated. Samples of Al, Cu, Fe are fabricated as metallic impurities, and measured electrical conductivity in the voltage range of 0~10 KV. Temperature dependent effect of hysteresis curves and the relationship between forward and reverse current due to impurity content are discussed.

제작방법에 따른 전력케이블용 폴리에틸렌 박막의 전기전도특성

조경순,이용우,이수원,홍진웅 한국전기전자재료학회 1997 電氣電子材料學會誌 Vol.10 No.5

In order to investigate the electrical conduction properties of polyethylene thin film for power cable with manufacturing methods, the thickness of specimen was the 30, 100[${\mu}{\textrm}{m}$] of LDPE and 200[${\mu}{\textrm}{m}$] of XLPE were manufactured. The experimental condition for conduction properties was measured until the breakdown occurs at temperature ranges from 30 to 110[$^{\circ}C$] and the electric field from 1$\times$10$^3$to 5$\times$10$^{6}$ [V/cm]. As for increase of temperature, the current density of LDPE was increased with constant ratio in low field, but changes with exponential function in high electric field. The tunnel current of pre-breakdown region is shifted toward low field as much as thermal excitation energy. At low electric field, the XLPE showed dominant electrical conduction properties by thermal excitation, and transformation of the electron was resisted by the crystal at high electric field.

(Na,K,Li)(Nb,Sb,Ta)O3계 세라믹스의 소성시간이 압전특성에 미치는 영향

김승원,류주현 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.4

본 연구에서는 우수한 압전 특성을 갖는 무연 압전 세라믹스를 개발하기 위해 0.99(Na0.52K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3+0.01(Sr0.95Ca0.05)TiO3+0.3wt%Bi2O3+ 0.3wt%Fe2O3 + 0.3wt%CuO 조성에 소성시간에 변화를 주어 NKN-SCT 세라믹스의 소성시간이 미세구조, 상구조 그리고 압전 및 유전특성에 미치는 영향을 조사한 결과, 모든 시편은 (202)/(020) 피크를 보이는 사방정계상(Orthorhombic Phase)을 나타내었다. 소성시간을 증가시킬수록 평균 입자의 사이즈는 1.84μm(1h), 4.05μm(3h), 9.68μm(5h), 5.49μm(7h), 5.18μm(9h)로 각각 나타났으며, 5시간 소성된 시편에서 최댓값 9.68μm를 나타내었다. 7시간 소성된 시편에서 압전상수(d33), 압전 전압상수(g33), 전기기계결합계수(kp), 기계적품질계수(Qm), 유전상수, (εr)는 각각 314 [pC/N], ,g33= 20.07 [10-3 mV/N], 0.442, 93, 1768 으로 에너지 하베스팅 소자 응용에 최적의 값을 나타내었다. In this paper, in order to develop excellent composition ceramics for a piezoelectric energy- harvestingdevice, we synthesized 0.99(Na0.52 K0.443 Li0.037)(Nb0.883 Sb0.08 Ta0.037)O3 + 0.01(Sr0.95 Ca0.05)TiO3 + 0.3 wt% Bi2O3 +0.3 wt% Fe2O3 + 0.3 wt% CuO (abbreviated as NKN-SCT) ceramics with different sintering times, using theordinary solid-state reaction method. The effect of sintering time on the microstructure and piezoelectric propertieswas investigated. The ceramics with the sintering time of 7 h have the optimum values of the piezoelectric constant(d33), piezoelectric voltage constant (g33), planar piezoelectric coupling coefficient (kp), mechanical quality factor(Qm), and dielectric constant (εr): d33= 314 [pC/N], g33= 20.07 [10-3 mV/N], kp = 0.442, Qm = 93, εr = 1,768, allbeing suitable for a piezoelectric energy-harvesting device.