• 센서학회지
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• 제9권4호
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• pp.297-306
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• 2000

최근 MEMS 소자의 성능향상을 위하여 수십 ${\mu}m$의 두께를 가지는 고형상비 단결정실리콘 구조물 제작에 관한 연구가 활발하게 진행되고 있다. 그러나 이러한 고형상비 단결정실리콘 구조물 제작 기술에서는 구조물의 구동 또는 전기신호의 검지를 위한 전극 사이의 전기적인 절연 방법이 주된 문제로서 대두되고 있다. 본 논문에서는 고형상비를 가지는 단결정실리콘 구조물 전극 간의 전기적 절연을 위하여 고형상비 산화막으로 구성된 빔 및 측벽을 이용한 새로운 절연 기술을 개발하였다. 개발된 절연 기술은 실리콘 구조물을 측면 또는 하부에서 산화막으로 지지하는 절연 구조를 가진다. 이러한 트렌치 산화막은 그 깊이가 수십 ${\mu}m$이므로 산화막의 잔류응력이 구조물에 미치는 영향을 반드시 고려하여야 한다. 본 논문에서는 PECVD 방법으로 증착한 TEOS 산화막으로 절연 구조들을 제작하였으며, 제작된 절연구조들의 잔류응력을 측정하고, 그 잔류응력이 구조물에 미치는 영향을 해석하였다. 또한 공진자를 이용하여 개발된 절연 기술이 고형상비 단결정실리콘 구조물에 효과적으로 쓰일 수 있음을 보였다.

• 센서학회지
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• 제22권3호
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• pp.175-180
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• 2013

This paper describes the characteristics of cubic silicon carbide (3C-SiC) films grown on a carbonized Si(100) substrate, using hexamethyldisilane (HMDS, $Si_2(CH_3)_6$) as a safe organosilane single precursor in a nonflammable $H_2$/Ar ($H_2$ in Ar) mixture carrier gas by atmospheric pressure chemical vapor deposition (APCVD) at $1280^{\circ}C$. The growth process was performed under various conditions to determine the optimized growth and carbonization condition. Under the optimized condition, grown film has a single crystalline 3C-SiC with well crystallinity, small voids, low residual stress, low carrier concentration, and low RMS. Therefore, the 3C-SiC film on the carbonized Si (100) substrate is suitable to power device and MEMS fields.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.342-344
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• 1995

Using piezoresistive effects of single-crystal and poly-crystalline silicon, pressure sensors of the same pattern were fabricated for comparison of temperature characteristics. Optimum size and aspect ratio of rectangular sensor diaphragm were calculated by FEM. For polsilicon pressure sensor, polysilicon resistors of Wheatstone bridge were deposited by LPCVD to be used in a wide' temperature range. Polysilicon pressure sensors showed more stable temperature characteristics than single-crysta1 silicon in the range of $-20\sim125[^{\circ}C]$. To get low TCO (Temperature Coefficient of Offset), below $\pm$3 [${\mu}V/V/^{\circ}C$], it is needed for each TCR of piezoresistors to have a deviation within $\pm25[ppm/^{\circ}C]$ less than $\pm500[ppm/^{\circ}C]$ of resistors for polysilicon pressure sensor can result in low TCS(Temperature Coefficient of Sensitivity) of -0.1[%FS/$^{\circ}C$].

• 비파괴검사학회지
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• 제36권1호
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• pp.1-8
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• 2016

Single crystalline silicon wafers having (100), (110), and (111) directions are employed as specimens for obtaining slowness profiles. Leaky Lamb waves (LLW) from immersed wafers were detected by varying the incident angles of the specimens and rotating the specimens. From an analysis of LLW signals for different propagation directions and phase velocities of each specimen, slowness profiles were obtained, which showed a unique symmetry with different symmetric axes. Slowness profiles were compared with elastic moduli of each wafer. They showed the same symmetries as crystal structures. In addition, slowness profiles showed expected patterns and values that can be inferred from elastic moduli. This implies that slowness profiles can be used to examine crystal structures of anisotropic solids.

• 한국전기전자재료학회논문지
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• 제30권5호
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• pp.301-306
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• 2017

Wire electrical discharge machining (WEDM) process was evaluated to slice Silicon (Si) for various applications. Specifically, various Si workpieces with various resistances, such as single and multi crystalline Si bricks and wafers were used. As conventional slicing processes, such as slurry-on or diamond-on wire slicing, are based on mechanical abrasions between Si and abrasive, there is a limitation to decrease the wafer thickness as well as kerf-loss. Especially, when the wafer thickness is less than $150{\mu}m$, wafer breakage increases dramatically during the slicing process. Single crystalline P-type Si bricks and wafers were successively sliced with considerable slicing speed regardless of its growth direction. Also, typical defects, such as microcracks, craters, microholes, and debris, were introduced when Si was sliced by electrical discharge. Also, it was found that defect type is also dependent on resistance of Si. Consequently, this study confirmed the feasibility of slicing single crystalline Si by WEDM.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.237-242
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• 2012

At present, crystalline solar cells take up a significant percentage of the solar industry. The ways of increasing the efficiency of crystalline solar cell are texturing and AR(Anti-Reflection) coating, and the purpose of these technologies is to increase the amount of available light on the solar cell by reducing the reflectivity. The reflectance of crystalline silicon solar cell combined with such technologies will be able to predict using the proposed simulation in this paper. The simulation algorithm was made using MATLAB, and it is a combination of the theories of reflection in textured wafer and in anti-reflection coated wafer. The simulation results were divided into three wavelength band and were compared with actual reflectance measured by a spectrometer. The wavelength band from 300 to 380 was named ultraviolet region and the wavelength band from 380 to 780 is named visible region. Finally, the wavelength band from 780 to 1200 named infrared region. When compared with measured reflection data, the simulation results had a small error from 0.4 to 0.5[%] in visible region. The error occurred in the rest two regions is larger than visible region. The extreme error occurred the infrared region is due to internal reflection effect, but in the ultraviolet region, the rationale on reduction phenomenon of reflectance occurred in small range did not proved. If these problem will be solve, this simulation will have high reliability more than now and be able to predict the reflectance of solar cells.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 2004년도 제35차 추계학술대회 및 제2회 HVEM 이용자 워크샵
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• pp.77-81
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• 2004

• 에너지공학
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• 제21권3호
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• pp.243-248
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• 2012

본 연구는 고온고습 시험을 통하여 Cell 레벨에서의 표면관찰 및 효율저하를 분석하였다. 고온고습 시험조건은 KS C IEC-61215에서 제시한 PV 모듈하의 조건을 이용하여 온도 $85^{\circ}C$, 습도 85%, 1000hr 동안 수행하였다. EL(Electroluminescence)촬영을 통하여 Cell 표면의 이상 유 무를 분석한 결과, 시간이 경과함에 따라, 부분적으로 표면이 손상되어 변색되는 것을 확인하였다. 고온고습 시험 전 단결정 Cell 및 다결정 Cell의 효율은 각각 17.7%, 15.5%였으며, 1000hr 수행 후 15.6%, 14.0%로 각각 11.9%와 9.3%의 감소율을 보였다. 또한, 경년 시 나타나는 전기적 특성을 분석하기 위하여 FF(Fill Factor)값을 분석한 결과, 고온고습 시험 후 단결정 Cell은 78.7%에서 75.0%로 4.7%, 다결정 Cell은 78.1%에서 76.7%로 1.8%의 감소율을 보였다. 태양전지 실리콘의 원자배열 및 순도에 따라 효율 변화에 영향을 받아 단결정 Cell이 다결정 Cell보다 효율저하가 크게 나타났다고 판단된다. 또한, FF감소율보다 효율 감소율이 크게 저하된 것을 확인할 수 있었으며, 이는 Cell의 외부환경적 요인에 의한 표면 손상이 p-n접합층 접촉저항과 경년 시 나타나는 FF 감소율보다 크게 영향을 준 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제15권3호
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• pp.281-286
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• 2002

In odder to investigate the magnetic properties of CoCr-based bilayered thin films on kind of underlayer, we introduced amorphous Si layer to Co-Cr(-Ta) magnetic layer as underlayer. First, we prepared CoCr and CoCrTa single layer using the Facing Targets Sputtering system to investigate theirs properties. It was revealed that with increasing the film thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. The CoCrTa thin film showed bettor crystalline and magnetic characteristics than CoCr thin film. As a result of investigating magnetic properties of CoCr and CoCrTa magnetic layer on introducing the Si underlayer, perpendicular coercivity and saturation magnetization of CoCr/Si and CoCrTa/Si bilayered thin film were decreased due to the increased grain size and diffusion of Si atoms to magnetic layer. And they showed constant with increasing the film thickness of Si thin film. However, in case of CoCrTa/Si bilayered thin film, in-plane coercivity was controlled low at about 250Oe. The c-axis orientations of CoCr/si and CoCrTa/Si bilayered thin film showed a good crystalline characteristics as about $2^{\circ}$.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.252-256
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• 2008

Photovoltaic (PV) modules output changes noticeable with variations in temperature and irradiance. In general it is has been shown that a $1^{\circ}C$ increase in temperature results in a 0.5% drop in output. In this paper, seven PV module types are analyzed for variation in temperature and irradiance, and the resulting output characteristics examined. The 7 modules types utilized are as follows; 3 poly crystalline modules, 2 single crystalline modules, 1 back contact single crystalline module and 1 HIT module. 3 groups of experiments are then conducted on the modules; tests with varying irradiance values, tests with module temperature varying under $25^{\circ}C$ and tests with module temperature varying over $25^{\circ}C$. The experiments results show that as temperature rises the follow is observed; Pmax decreases by 0.6%, Voc decreases by about 0.4%, and Isc increasing by between 0.03%${\sim}$0.08%. In addition, an irradiance decrease of 100 w/m2 translates into a 10% drop in Pmax.