• Korean Journal of Materials Research
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• v.10 no.5
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• pp.369-374
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• 2000

In order to investigate the effects of addition of 1M sulfuric acid to the etching solution or 1M hydrochloric acid on the etching behavior of aluminum foil for electrolytic capacitors, the changes in the density of etch pit, the length and diameter of etch tunnels and the capacitance were analyzed using SEM, TEM, LCR meter etc. Sulfate ion as a corrosion inhibitor was contributed to the increase of the surface area comparing with chloride ion. By adding sul-furic acid the density of etch pit and the length of etched tunnel increased and the diameter of the tunnel decreased, resulting in the increase of capacitance. It was also shown that the capacitance decreased when the current density was below $0.9A/\textrm{cm}^2$, while remarkably increased in the other case.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.54-57
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• 2009

The propellant level measurement system of the next Koreanized launch vehicle shall adapt a capacitive type sensor, which can generate capacitive values continuously considering cryogenic environment and the characteristics of flowrate control. At present there are a twin-arc and a triple-arc methods as a capacitive type signal sensing method. In this study a highly accurate triple-arc method, which can apply to almost all fluids, is chosen. In this paper the review results on the principle of triple-arc sensing, the analysis results on the influence on capacitive values due to shape change of sensing part, and the simulation results to monitor the influence on signal sensing according to the location of sensing part in the upper part of propellant tank are included. Information obtained from this study can be used in the designing and manufacturing of on-board propellant level measurement system in tanks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.27-32
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• 2003

This paper describes to extend the fast algorithm fur the capacitance extraction of large three-dimensional object. The triangular meshes are used and refined adaptively in the area where the heavy charges reside in each iterative solving. This technique is applied to the capacitance extraction of a 68-pin cerquad package. The results show fast convergence, and this adaptive technique coupled with the fast algorithm is efficient to reduce the number of elements and computing time with least additional computational efforts in large three dimensional problems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.509-512
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• 2015

In this paper, several capacitive sensors for measuring the position of the piston in hydraulic cylinder was studied and designed. The inductive LVDT sensor has been widely used to measure the position of the piston because of its high accuracy, but this type of sensor is very expensive and has difficulty in use because of its complexity. To overcome these disadvantages, we studied the optimized non-contact capacitive sensors and designed several capacitive sensors for accurate measuring the location of piston in hydraulic cylinder. The proposed capacitive sensor has the possibility of practical use for hydraulic cylinder through experiments.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.7
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• pp.1-6
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• 2004

For MOSFET devices with nanometer range gate length, accurate extraction of effective gate length is highly important because transistor characteristics become very sensitive to effective channel length. In this paper, we propose a new approach to extract the effective channel length of nanometer range MOSFET by Capacitance Voltage(C-V) method. The effective channel length is extracted using gate to source/drain capacitance( $C_{gsd}$). It is shown that 1/$\beta$ method, Terada method and other C-V method are inadequate to extract the accurate effective channel length. Therefore, the proposed method is highly effective for extraction of effective channel length of 100nm CMOSFETs.s.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.61-67
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• 2004

The structural, electrical properties of the electrolytic capacitors were examined. By the addition of additives to hydrochloric acid solution increased the dielectric aluminum surface layer. For etch tunnels formed in hydrochloric acid, the away and density of the tunnels was not uniform, while for those formed in hydrochloric acid with additives the distribution presented relative uniformity. When the etched surface formed in hydrochloric acid with $5\%$ ethylene glycol, the enlargement of specific surface area was more effective.

• Polymer(Korea)
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• v.36 no.4
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• pp.519-524
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• 2012

Capacitance measurements of the polymer light-emitting diodes (PLEDs) with conjugated polyelectrolyte (CPE) electron transporting layers (ETLs) provide important information of device physics for understanding the function of CPEs as ETLs, together with current density-voltage-luminescence measurements. We investigated the counterion-dependent capacitance behaviors that present a highly negative or positive capacitance at the low frequency, and suggested different carrier injection mechanisms. Capacitance model study reveals that the electron injection mechanism can be described either by the dipole alignment scheme or by electronic charge carrier accumulation at the cathode/ETL/emission layer interfaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.947-950
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• 2004

[ $ZnCr_2O_4$ ]에 $Li_2CO_3$를 $5{\sim}30wt%$ 범위에서 정량적으로 첨가한 감습재료에서 screen printing법으로 알루미나 기판 위에 후막으로 인쇄하고 $650\sim750^{\circ}C$에서 소결하여 후막 습도센서를 제작하였으며, $30\sim90%RH$ 범위에서 상대습도에 따른 저항 및 정전용량 특성을 조사하였다. $ZnCr_2O_4$에 $Li_2CO_3$가 5wt%가 첨가된 조성의 센서는 70%RH이상에서, 25wt%이상 첨가된 조성의 센서는 40%RH이하에서 저항 및 정전용량이 급격히 변화하는 switching 현상을 나타내었다. 반면, $ZnCr_2O_4$에 $Li_2CO_3$가 15wt%가 첨가된 조성의 센서는 선형적으로 저항은 감소하였고, 정전용량은 증가하였다.

• Journal of IKEEE
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• v.28 no.2
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• pp.158-167
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• 2024

In this study, U-net model based on electrical capacitance is applied to monitor the condition inside the pipeline of semiconductor rear end process implemented in the numerical simulation. Capacitance values measured from electrodes attached to the pipeline is used as input data for the U-net network model and estimated permittivity distribution by the U-net model is used to reconstructed cross-sectional image at the pipeline. In the numerical simulation, images reconstructed by U-net model, Fully-connected neural network (FCNN) model and Newton-Raphson method are compared for evaluation. U-net model shows good results as compared to other models.

• Journal of Sensor Science and Technology
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• v.8 no.1
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• pp.32-37
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• 1999

A capacitance-type humidity sensor with mesa structure in which porous silicon layer is used as humidity-sensing material is developed and its humidity sensing properties are measured. This sensor has a structure where two electrodes are set on the up-side of the wafer against the past typical structure having these electrodes on the up and down-side of the wafer. Therefore, the sensor can be fabricated monolithically to be more compatible with the IC process technology, and is possible to detect more correct output capacitance by removing the effect of the parasitic capacitance from the bottom layer and other junctions. To do this, the sensor was fabricated using process such as localized formation of porous silicon, oxidation of porous silicon layer, and etching of oxidized porous silicon layer. From the completed samples, the dependence of capacitance on the relative humidity of 55 to 90% more was measured at room temperature. As the result, the measured capacitance increased monotonously higher at the low frequency of 120 Hz, where the capacitance was observed to increase over 300%.