발전기 스테이터의 냉각코일에 pinhole 발생을 검지할 수 있는 수소센서 개발

최시영(Sie-Young Choi) 대한전기학회 1999 대한전기학회 학술대회 논문집 Vol.1999 No.11

SUS630 다이아프램을 이용한 반도체식 로드셀

문영순 ( Young Soon Moon ),이선길 ( Seon Gil Lee ),류상혁 ( Sang Hyuk Ryu ),최시영 ( Sie Young Choi ) 한국센서학회 2011 센서학회지 Vol.20 No.3

The load cell is a force sensor and a transducer that is used to convert a physical force into a electrical signal for weighing equipment. Most conventional load cells are widely used a metal foil strain gauge for sensing element when force being applied spring element in order to converts the deformation to electrical signals. The sensitivity of a load cell is limited by its low gauge factor, hysteresis and creep. But silicon-based sensors perform with higher reliability. This paper presents the basic design and development of the silicon type load cell with an SUS630 diaphragm. The load cell consists of two parts the silicon strain gauge and the SUS630 structure with diaphragm. Structure analysis of load cell was researched by theory to optimize the load cell diaphragm design and to determine the position of peizo-resistors on a silicon strain gauge. The piezo-resistors are integrated in the four points of silicon strain gauge processed by ion implantation. The thickness of the silicon strain gauge was polished by CMP under 100 μm. The 10 mm diameter SUS630 diaphragm was designed for loads up to 10 kg with 300 μm of diaphragm thickness. The load cell was successfully tested, the variation of ΔR(%) of four points on the silicon strain gauge is good linearity properties and sensitivity.

$Al_{2}O_{3}$가 첨가된 지르코니아 산소센서의 제조 및 그 특성

손정덕,최시영,Sohn, Jeong-Duk,Choi, Sie-Young 한국센서학회 1992 센서학회지 Vol.29 No.3

이트리아 안정화(安定化) 지르코니아(92 mole% $ZrO_{2}$+8 mole% $Y_{2}O_{3}$)에 0.5 mole% $SiO_{2}$와 $0{\sim}2.0{\;}mole%{\;}Al_{2}O_{3}$가 첨가된 소결체의 소결성, 기계적 및 전기적 성질에 대하여 조사하였다. 소결밀도(燒結密度)는 0.5 mole% $Al_{2}O_{3}$가 첨가되었을 때 가장 높게 나타났으며 1.5 mole%이상 $Al_{2}O_{3}$가 첨가됨에 따라 감소하는 경향을 나타내었다. 비커스 경도(硬度)는 소결밀도(燒結密度)에 비례하여 나타났으며, 0.5 mole% $Al_{2}O_{3}$가 첨가되었을 때 가장 높은 전도성을 나타내었다. 일정한 산소분압(酸素分壓)에 따른 기전력 측정에서도 0.5 mole% $Al_{2}O_{3}$가 첨가되었을 매 가장 높았다. 제작된 산소(酸素)센서들의 응답특성(應答特性) 결과에서 $SiO_{2}$와 $Al_{2}O_{3}$가 각각 0.5 mole% 첨가된 센서의 응답특성이 가장 좋았다. Sinterability, mechanical and electrical properties of yttria-stabilized zirconia(92 mole% $ZrO_{2}$+8 mole% $Y_{2}O_{3}$) doped with 0.5 mole% $SiO_{2}$ and $0{\sim}2.0 mole%{\;}Al_{2}O_{3}$ were studied as a function of $Al_{2}O_{3}$ addition. Sintered density increased with increasing $Al_{2}O_{3}$ addition up to 0.5 mole % but leveled off with further addition. Victors hardness is proportional to sintered density. The specimen with 0.5 mole% $Al_{2}O_{3}$ and 0.5 mole% $SiO_{2}$ exhibited the maximum electrical conductivity and revealed a maximum electromotive force for a given oxygen partial pressure. Experimental voltage curve of this oxygen sensor take on a sharper, more steplike transition at the stoichiometric A/F ratio than those of other commercial oxygen sensors.

InSb MIS 구조에서의 계면의 전기적 특성 평가

이재곤,최시영 ( Jae Gon Lee,Sie Young Choi ) 한국센서학회 1996 센서학회지 Vol.5 No.6

The interfacial electrical properties of InSb MIS structure with low temperature remote PECVD SiO₂ have been characterized. The interface-state density at mid-bandgap of the MIS structure was about 1∼2 x 10^(11) cm^(-1)eV^(-1), when the SiO₂ film was deposited at 105℃. However, large amount of interface states and trap states were observed in the MIS structure fabricated at temperatures above 150℃. The time constant of 10 ^(-4)∼10^(-5) sec of interface states was extracted from G-V measurement. As the deposition temperature increased, the hysteresis of C-V curves were increased due to the high trap density.

Al2O3가 첨가된 지르코니아 산소센서의 제조 및 그 특성

손정덕,최시영 ( Jeong Duk Sohn,Sie Young Choi ) 한국센서학회 1992 센서학회지 Vol.1 No.1

Sinterability, mechanical and electrical properties of yttria-stabilized zirconia(92 mole % ZrO₂+8 mole % Y₂O₃) doped with 0.5 mole % Si₂O₃ and 0∼2.0 mole % Al₂O₃ were studied as a function of Al₂O₃ addition. Sintered density increased with increasing Al₂O₃ addition up to 0.5 mole% but leveled off with further addition. Vickers hardness is proportional to sintered density. The specimen with 0.5 mole % Al₂O₃ and 0.5 mole % SiO₂ exhibited the maximum electrical conductivity and revealed a maximum electromotive force for a given oxygen partial pressure. Experimental voltage curve of this oxygen sensor take on a sharper, more steplike transition at the stoichiometric A/F ratio than those of other commercial oxygen sensors.

PLT 박편을 이용한 압전특성이 보상된 초전형 적외선 센서의 제작

김영일,노용래,최시영 ( Young Eil Kim,Yongrae Roh,Sie Young Choi ) 한국센서학회 1997 센서학회지 Vol.6 No.1

Highly sensitive pyroelectric IR sensors were fabricated with La-modified PbTiO₃(PLT) thin plates compensating for piezoelectric effect. The device was fabricated in a dual form by placing two PLT cells, each of 1 X 2 ㎟, side by side with appropriate electrode configuration. The dual element sensor had a signal to noise ratio of about 350 that was much larger than That of single element sensors. Further the dual element sensors exhibited excellent pyroelectric properties such as a large voltage responsivity of 2400 V/W, a pyro-coefficient of 4.6 X 10^(-8)C/㎠K, a voltage figure of merit of 4.2 X 10^(-11) Ccm/J, and a small thermal time constant of 8.7 msec. It was confirmed through experiments that the dual element sensor was applicable to detect the two-dimensional moving direction of human beings.

산화된 다공질 폴리실리콘 전계방출 소자의 픽셀별 구동 및 특성

유성원,김진의,최시영,You, Sung-Won,Kim, Jin-Eui,Choi, Sie-Young 대한전자공학회 2007 電子工學會論文誌-SD (Semiconductor and devices) Vol.44 No.8

본 논문에서는 산화된 다공질 폴리실리콘을 이용하여 전계 방출 소자를 제작하여, 각각의 픽셀에 따른 전기적 특성과 형광체의 발광 특성을 조사하였다. 실제 대면적 디스플레이 소자에 적용하기 위해서 PM 방식을 이용해서 소자를 픽셀별로 동작하였고, 상부금속 전극의 어레이에 따른 두께와 폭의 공정조건을 확립하였다. 산화된 다공질 폴리실리콘의 미세 구조를 분석하고, 각각의 픽셀에 따른 전계방출 특성을 조사해 보았다. 상부금속 전극의 두께와 폭에 따른 전자방출 특성을 조사해 본 결과 Ti/pt(2nm/7nm)가 가장 적절한 두께라는 것을 확인 할 수 있었고, 2.5 mm 이상 폭에서 전자방출 효율이 증가하는 모습을 확인 할 수 있었다. 각 픽셀에 따른 소자의 전기적 특성은 픽셀마다 조금씩의 차이는 있지만 거의 동일한 누설 전류와 방출 전류가 나타남을 확인할 수 있었고, 동일한 크기의 효율도 관찰할 수 있었다. 누설 전류와 방출 전류는 시간이 증가함에 따라 감소하는 모습이 나타나긴 하였으나, 모든 픽셀이 거의 동일하게 감소하였다. 각각의 픽셀에 따른 휘도는 큰 차이가 없음을 확인할 수 있었고, 20 V에서 $700cd/m^2$ 이상의 높은 휘도를 나타내었으므로 실제 디스플레이 소자로도 응용이 가능할 것이다. In this paper, we fabricated the field emitter display using oxidized porous polysilicon(OPPS). Their field emission characteristics and the brightness were investigated for each pixel. The OPPS emitter was operated to each pixel using passive matrix for application of large panel display. We set up the proper thickness and width of upper electrode. The fine structure of OPPS was analyzed and the field emission characteristics of each pixel were investigated. As a result of field emission characteristics of different upper electrode thickness and width, we confirmed that the most efficient thickness was 2nm/7nm and increased the emission efficiency over the width of 2.5 mm. Even if field emission characteristics of each pixel was a little different but we confirmed the same leakage current and emission current, emission efficiency at each pixel. The leakage current and emission current was decreased according to the time increases but all of each pixel were uniformly decreased. We confirmed that the brightness of each pixel was not different and the brightness of OPPS field emitter was 700 cd/m2 at the Vps=20 V. Accordingly, the patterned OPPS field emitter can be applied to high quality field emission display devices.

빔 위치변화에 따른 4빔 압저항형 실리콘 가속도 센서의 제조 및 특성비교

신현옥,손승현,최시영,Shin, Hyun-Ok,Son, Seung-Hyun,Choi, Sie-Young 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.7

4빔 브릿지형 압저항형 실리콘 가속도 센서에서 빔의 위치가 가속도 센서의 특성에 어떤 영향을 주는지 조사하기 위해서 빔의 위치가 서로 다른 3가지 형태의 가속도 센서를 FEM(finite element method)을 사용하여 해석하고, SDB(silicon direct bonding) 웨이퍼를 사용하여 RIE(reactive ion etching)와 KOH(potassium hydroxide) 애칭 공정으로 제조하였다. 세가지 형태의 가속도 센서에 대한 FEM 해석 경과, 첫 번째 공진 주파수와 Z축 감도는 세구조 모두 같게 나타났으나, 두 번째와 세 번째의 공진 주파수 및 X, Y축의 감도는 다른 것으로 나타났다. 제조된 가속도 센서의 특성을 살펴볼 때, 세 가지 형태의 센서는 비록 첫 번째 공진 주파수와 Z축 감도가 정확하게 일치하지는 않았지만, 첫 번째 공진 주파수는 1.3 ~ 1.7 KHz, Z축 감도는 5 V 인가시 180 ~ 220 lN/G, 타축감도는 1.7 ~ 2 %를 가지는 것으론 나타났다. In order to examine the effect of beam location n the performance of bridge type piozoresistive silicon accelerometer, three sensors having different location of beams were simulated by FEN(finite element method) and fabricated by RIE(reactive ion etching) and KOH etching method using SDB(silicon direct bonding) wafer, Results of the FEM simulation present that the 1st resonace frequency and Z axis sensitivity of each sensor are identical but the 2nd, and the 3rd resonace frequency and X, Y axis sensitivity are different. Even though the 1st resonance frequency and Z axis sensitivity measured from fabricated sensors do not perfectly coincide with each other, all 3 type sensors present 180 ~ 220N/G of Z sensitivity at 5 V supply voltage and 1.3 ~ 1.7kHz of the 1st resonance frequency and about 2% of lateral sensitivity.

사각뿔 형태의 Mass 보상된 실리콘 압저항형 가속도 센서

손병복,이재곤,최시영 ( Byoung Bok Sohn,Jae Gon Lee,Sie Young Choi ) 한국센서학회 1994 센서학회지 Vol.3 No.1

When etching rectangular convex corners of silicon using anisotropic etchants such as KOH, deformation of the edges always occurs due to undercutting. Therefore, it is necessary to correct the mass pattern for compensation. Experiments for the compensation method to prevent this phenomenon were carried out. In the result, the compensation pattern of a regular square is suitable for acceleration sensors considering space. With this consequence, silicon piezoresistive acceleration sensor with compensated square pillar type of mass has been fabricated using SDB wafer.

실리콘 마이크로머시닝과 RIE 를 이용한 가속도센서의 제조

김동진,김우정,최시영 ( Jin Dong Kim,Woo Jeong Kim,Sie Young Choi ) 한국센서학회 1997 센서학회지 Vol.6 No.6

A piezoresistive acceleration sensor for 50 G has been fabricated by silicon micromachining method using SDB(silicon direct bonding) wafer. The structure of the piezoresistive acceleration sensor consists of ai seismic square pillar type mass and four beams. $quot;This structure was fabricated by reactive ion etching and chemical etching using KOH-etchant. The rectangular square structure is used in order to compensate the deformation of the edges due to underetching. The fabricated sensor showed a linear output voltage-acceleration characteristics and its sensitivity was about 88 ㎶/V·g from 0 to 10 G.