Reversible capacitance changes in the MOS capacitor with an ITO/CeO₂/p-Si structure

Park, Daehoon,Kim, Minju,Beom, Keonwon,Cho, Seong-Yong,Kang, Chi Jung,Yoon, Tae-Sik Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.786 No.-

<P><B>Abstract</B></P> <P>A reversible capacitance changes with respect to the polarity of applied voltage is demonstrated in a MOS (metal-oxide-semiconductor) capacitor consisting of a high-k CeO<SUB>2</SUB> and oxygen-reactive indium-tin-oxide (ITO) electrode on p-Si substrate, i.e., an ITO/CeO<SUB>2</SUB>/p-Si structure. The capacitance-voltage (<I>C</I>-<I>V</I>), capacitance-time (<I>C</I>-<I>t</I>), and voltage-pulse measurements exhibit consistently that the accumulation capacitance is gradually increased upon repeatedly applying negative voltage to the ITO, while the depletion capacitance is reversibly decreased upon applying positive voltage. Particularly, the capacitance change is observed even at a low voltage of ±0.5 V from the device with 40-nm-thick CeO<SUB>2</SUB> layer. The capacitance change is further enhanced as increasing measurement temperature from 25 to 100 °C, implying that the capacitance change is associated with the thermally activated process under the applied voltage. In addition, the resistance of ITO gate electrode is found to decrease upon applying negative voltage, but it is increased reversibly upon applying positive voltage. The reversible capacitance changes in the MOS capacitor with oxygen-reactive ITO gate electrode are explained with voltage-driven oxygen ion migration between ITO and CeO<SUB>2</SUB> layers that can alter the CeO<SUB>2</SUB> dielectric permittivity and induce the gate depletion in the ITO. These reversible capacitance changes have a potential to be employed to modulate the MOSFET (MOS field-effect-transistor) properties such as on-state current, threshold voltage, and transconductance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polarity-dependent reversible capacitance changes in an ITO/CeO<SUB>2</SUB>/p-Si structure. </LI> <LI> Capacitance changes through voltage-driven oxygen migration between ITO and CeO<SUB>2</SUB>. </LI> <LI> Application of reversible capacitance changes to modulate the MOSFET properties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A study on stray capacitance of ferrite Common Mode Chokes for EMI filters

Guangdong Dong,Fanghua Zhang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The stray capacitance of CM chokes consists of the material capacitance and the winding parasitic capacitances. The material capacitance is determined by the intrinsic material properties of the ferrite core. The influence of ferrite core material on stray capacitance of CM chokes are researched. The complex magnetic permeability (CMP) of a ferrite core is measured and the CMP characteristic is analyzed. The behavior of the material capacitance is inversely proportional to the square of turn N. Winding parasitic capacitances include turn-to-turn capacitance and turn-to-core capacitance. An analytical method is adopted to calculate the winding parasitic capacitances taking into the core physical construction and material properties. Based on the capacitance network model, the stray capacitance can be derived. The impedance characteristic of a CM choke is tested using impedance analyzer to extract the stray capacitance, and the analytical result is consistent with the measured result.

Capacitive biosensor based on vertically paired electrode with controlled parasitic capacitance

Lee, Ga-Yeon,Park, Jun-Hee,Chang, Young Wook,Kang, Min-Jung,Cho, Sungbo,Pyun, Jae-Chul Elsevier 2018 Sensors and actuators. B Chemical Vol.273 No.-

<P><B>Abstract</B></P> <P>A capacitive biosensor based on vertically paired electrodes with controlled parasitic capacitance is presented to improve the sensitivity of capacitive measurement. The vertically paired electrodes were fabricated with a parylene film as a dielectric layer, with the distance between the electrodes less than hundreds of nanometer. The problem of parasitic capacitance owing to the electrode configuration was analyzed according to the superposed area of the electrode. In this work, two kinds of vertically paired electrodes were fabricated to control the parasitic capacitance—square-type and circular-type electrodes with different superimposed areas of 21.8 (100%) and 9.3 (42%) mm<SUP>2</SUP> and the same electrode area of 9.4 × 10<SUP>−5</SUP> mm<SUP>2</SUP>, respectively. The effect of superimposed area of the vertically paired electrodes on capacitive measurement was analyzed using the electrodes. The sensitivity of capacitive measurement was observed to increase with a decrease in superimposed electrode area and frequency. Further, the effect of parasitic capacitance was estimated by computer simulation of the sensitivity of impedance and capacitive measurement when 10% change in <I>R</I> <SUB>S</SUB> or <I>C</I> <SUB>S</SUB> occurred. The results showed that adsorption of proteins could be sensitively measured when the parasitic capacitance decreased. Finally, the effect of superimposed area of the vertically paired electrodes was measured from the interaction between antigens (human serum albumin, HSA) and immobilized antibodies (anti-HSA antibodies).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two types of vertically paired electrodes with controlled parasitic capacitance was developed. </LI> <LI> The influence of parasitic capacitance was estimated for capacitive measurement on protein adsorption. </LI> <LI> Finite element method simulation was used for studying of the influence of parasitic capacitance on the sensitivity of impedance measurement. </LI> <LI> Immunoassay was presented on two types of vertically paired electrodes with controlled parasitic capacitance. </LI> </UL> </P>

전원 잡음을 줄이기 위한 평면계획 단계에서의 Decoupling Capacitance 할당

허창룡,임종석,Heo Chang-Ryong,Rim Chong-Suck 대한전자공학회 2005 電子工學會論文誌-SD (Semiconductor and devices) Vol.42 No.9

본 논문에서는 평면계획 단계에서 모듈의 전원 잡음을 줄이기 위해 필요한 decoupling capacitance를 효과적으로 할당하는 방법을 제시한다. 먼저, 각 모듈의 decoupling capacitance가 과대평가되고 추가 면적 삽입으로 모듈의 전원 잡음이 변하는 기존 접근 방법의 문제점을 살펴보고, 이를 해결할 수 있는 새로운 방법을 제시한다. 또한, 선형프로그래밍 방법보다 빠른 시간 내에 decoupling capacitance 면적을 위한 빈 공간을 할당하는 간단한 휴리스틱 방법을 제안한다. 실험결과에서 제시된 방법은 Zhao[4]의 방법과 비교하여 decoupling capacitance 면적이 평균 $7.9\%$ 감소하고, 이로 인해 평면계획 결과의 전체 면적과 와이어 길이가 감소하였다. 또한, 추가 면적 삽입으로 인한 모듈의 전원 잡음 문제를 잘 해결하고 있음을 확인하였다. 수행시간 비교에서는 평균 $11.6\%$의 향상을 보였다. This paper proposes a method which efficiently allocates decoupling capacitance to reduce power supply noise at the floorplan level. We observe problems of previous approach that the decoupling capacitance of each module was overestimated and the power supply noises of modules were changed by inserting additional area for decoupling capacitance, and then suggest a new approach. And, we also present a simple heuristic method which can effectively allocate white space modules for decoupling capacitance area within more faster time instead of LP technique. Experimental results show that our approach can reduce the area of decoupling capacitance to average 7.9 percent compared with Zhao's approach in [4]. Therefore both total area and wire length of nniflm result are decreased. Also, we confirm that our approach solves well the problem caused by inserting additional area. In execution time comparison, our approach shows average 11.6 percent improvement.

우리나라 고용량 MLCC 기술 개발의 역사와 전망

홍정오,김상혁,허강헌 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.2

MLCC (Multi-layer Ceramic Capacitor) is the most important passive component in electronic devices such as HHP, PC and digital display. The development trend of MLCC is a miniaturization with increasing the capacitance. In this paper, a development history of the high capacitance MLCC in Korea was introduced, and the necessity of the finer BaTiO₃ was explained in the viewpoint of the issued electrical and dielectric properties of high capacitance MLCC. The bottleneck technologies to realize the high capacitance was shortly introduced, followed by the prediction of the development trend of MLCC in near future. MLCC (Multi-layer Ceramic Capacitor) is the most important passive component in electronic devices such as HHP, PC and digital display. The development trend of MLCC is a miniaturization with increasing the capacitance. In this paper, a development history of the high capacitance MLCC in Korea was introduced, and the necessity of the finer BaTiO₃ was explained in the viewpoint of the issued electrical and dielectric properties of high capacitance MLCC. The bottleneck technologies to realize the high capacitance was shortly introduced, followed by the prediction of the development trend of MLCC in near future.

Capacitance 측정법을 이용한 나노 SiC 에폭시 복합재료의 내부 강화재 분산 예측방법

권동준 ( Dong Jun Kwon ),왕작가 ( Zuo Jia Wang ),김제준 ( Je Jun Kim ),장기욱 ( Key Wook Jang ),박종만 ( Joung Man Park ) 한국복합재료학회 2013 Composites research Vol.26 No.6

나노입자를 이용하여 강화 효과를 높이기 위해서는 고분자 기지 내부의 균일한 분산 상태를 확보하여야 한다. 또한 균일분산 조건 확보 후 균일 분산상태를 증명할 평가자료가 필요하다. 본 연구는 에폭시 수지와 SiC 나노입자를 혼합한 SiC/에폭시 복합 수지를 제조할 경우 커패시턴스 측정법을 이용한 강화재 분산도 예측 연구를 진행하였다. 커패시턴스는 전기용량을 의미하며 측정 재료의 내부 전하량과 비례한다. 기존 에폭시 수지에 비해 나노 SiC 입자를 함유할 경우 전하량이 증가되는 이론을 바탕으로 구간별 커패시턴스 측정에 따른 분산도 평가를 진행하고, 커패시턴스 분산도 예측방법에 대한 타당성을 FE-SEM과 물리적 강도 증가 방법으로 평가하였다. 소니케이션 분산 방법과 교반기 분산 방법을 이용하여 분산 방법에 따른 SiC 나노입자 분산도 상태를 비교하였다. 인장강도와 커패시턴스 간의 상관관계가 있었으며, 파단면에 대한 비교를 할 때 분산성 향상에 대한 차이를 확인할 수 있었다. The good dispersion of nano-materials in epoxy matrix was important parameter for the reinforcement effect, and the evaluation of dispersion degree was to prove it. This work was studied to predict the dispersion condition of nano-SiC powders in SiC/epoxy composites using capacitance measurement. Capacitance was defined to be the electric capacity in proportional to electron charge of the measuring section. In case of nano-SiC powders, the electron charge of SiC/epoxy composites was higher than that of neat epoxy resin. Capacitance was evaluated for each section of SiC/epoxy composites. The prediction of dispersion condition was verified by using capacitance measurement. Dispersion condition of nano-SiC powders in epoxy matrix was evaluated with two different dispersion methods, i.e., sonication and stirring methods. The dispersion degree was also verified with the tensile strength correlating to capacitance.

Impedance characteristics and electrical double-layer capacitance of composite polystyrene–cobalt–arsenate membrane

Tanvir Arfin,Neetu Yadav 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.1

In continuation of our previous work with composite polystyrene–cobalt–arsenate (PS–Co–As), we further extended impedance measurements. All calculations reported were extracted from experiments carried out in the frequency range of 1–5 kHz and different concentrations (0.0001 c(M) 1) of KCl and NaCl at isothermal temperature (25 0.1 8C). The membrane capacitance and resistance measurements were observed to depend on the concentration and the applied frequency of the electrolyte. The observed capacitances and resistances were used to calculate the membrane resistances (RM), capacitance (CM),reactance (XX), and also derive the impedance (Z). At higher frequencies, the capacitances became low and the impedance decreased with increasing frequency with a corresponding increase in the measured phase angle. On the other hand at the highest frequencies attainable, the phase angle became low. At low frequencies, the phase angle was become independent of the cation, while the impedance showed a clear dependence. The diffused double-layer polarization charge on the geometric capacitor played important role by affecting the overall membrane capacitance. The applied frequencies affected the double-layer capacitance due to the movement of ions across the membrane. At the membrane–electrolyte interface, the electrical double-layer was influenced in addition to being controlled by the transport of ions.

Single-cell capacitance analysis of NIH/3T3 cells using an impedance biosensor

Kang Dahyun,Kim Yeeun,Lee Gayoung,Choi Jisoo,Yang Jeongmok,Jang Moongyu 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.83 No.11

Biosensors have emerged as promising tools for the analysis of single-cell growth. This study focuses on the fabrication of an impedance biosensor to monitor the growth of NIH/3T3 cells by measuring changes in their capacitance over time. The results showed an increase in capacitance corresponding to the growth of the cells. However, it was observed that the capacitance behaved diferently in the early (0–2.33 h) and late (2.33–48 h) stages of cell growth. In the early stage, the cells in the medium were still in a sinking state, whereas in the late stage, most of the cells were in contact with the sensor surface, undergoing growth and division. As a result, the late-stage capacitance was higher than the early stage capacitance. The average capacitance values of a single cell were recorded at diferent frequencies and showed the same phenomenon at all frequencies.

흡연이 十二原穴의 체표 capacitance에 미치는 영향

김양섭(Yang-Seob Kim),박영춘(Young-Chun Park),임윤경(Yun-Kyoung Yim) 대한한의학회 2015 대한한의학회지 Vol.36 No.3

Mn-doped activated carbon aerogel as electrode material for pseudo-capacitive supercapacitor: Effect of activation agent

Lee, Yoon Jae,Park, Hai Woong,Hong, Ung Gi,Song, In Kyu Elsevier 2012 Current Applied Physics Vol.12 No.4

<P><B>Abstract</B></P><P>Carbon aerogel (CA) was prepared by a sol-gel polymerization of resorcinol and formaldehyde, and a series of activated carbon aerogels (ACA-X, <I>X</I> = H<SUB>3</SUB>PO<SUB>4</SUB>, K<SUB>2</SUB>CO<SUB>3</SUB>, KOH, and ZnCl<SUB>2</SUB>) were then prepared by a chemical activation using different activation agent (<I>X</I> represented an activation agent). Specific capacitances of activated carbon aerogels were measured by cyclic voltammetry and galvanostatic charge/discharge methods in 6 M KOH electrolyte. Among the samples prepared, ACA-K<SUB>2</SUB>CO<SUB>3</SUB> showed the highest specific capacitance (152 F/g). In order to combine excellent electrochemical performance of activated carbon aerogel with pseudo-capacitive property of manganese oxide, 7 wt% manganese oxide was doped on activated carbon aerogels (Mn/ACA-X) by an incipient wetness impregnation method. Capacitance measurements revealed that Mn/ACA-K<SUB>2</SUB>CO<SUB>3</SUB> showed the highest specific capacitance (189 F/g). The enhanced capacitance of Mn/ACA-K<SUB>2</SUB>CO<SUB>3</SUB> was attributed to the fine pore structure and outstanding electric properties of activated carbon aerogel as well as the faradaic redox reactions of manganese oxide.</P> <P><B>Highlights</B></P><P>► Activated carbon aerogels (ACA-X, <I>X</I> = H<SUB>3</SUB>PO<SUB>4</SUB>, K<SUB>2</SUB>CO<SUB>3</SUB>, KOH, ZnCl<SUB>2</SUB>) were prepared. ► Manganese oxide supported on ACA-X (Mn/ACA-X) was prepared. ► Among ACA-X, ACA-K<SUB>2</SUB>CO<SUB>3</SUB> showed the highest specific capacitance. ► Among Mn/ACA-X, Mn/ACA-K<SUB>2</SUB>CO<SUB>3</SUB> showed the highest specific capacitance.</P>