RF스퍼터링법으로 제작한 ZnO박막의 특성평가

정세민,정광천,최유신,김도영,김철수,이준신 성균관대학교 1997 학술회의지원논문목록집 Vol.1997 No.-

ZnO shows the properties of wide conductivity variation, high optical transmittance, and excellent piezoelectricity. Using these properties of ZnO, the material applications were extended to sensors, SAW filters, solar cells, and display devices. This paper investigated transmittance influenceing factors for thin film. ZnO grown by RF magnetron sputtering. The growth rate and structural investifation were carried out in conjuction with optical transmittance characteristics of thin film ZnO. THe glass substrate temperature of 175°C exhibited a preferrential crystallization along (002)orientation. Transmittance of ZnO film deposited at the substrate temperature of 175°C showed higher than 92%. An active sputter gas was investigated with a variation of O₂partial pressure from 0 to 100% in an Ar atmosphere. ZnO film grown in 100% Ar gas shws that a reduced transmittance of 82% at the short wavelengths and decreased resistivity value. As the partial pressure of O₂gas increased the optical transmittance was increased above 90% at the short wavelengths, however, resistivity was drastically increased to higher than 10⁴Ω-cm.

LiNbO₃單結晶의 c-axis 熱膨脹係數測定에 관한 考察

丁世敏 東亞大學校 1980 東亞論叢 Vol.17 No.2

The main difference between V.V.Zhdanova et al. and Y.S.Kim et al. is the being of anisotropy in the thermal expansion coefficient variation with temperature. To see this, the optical dilatometer is constructed with Michelson-Morley interferometer and microscope. As a result, strong anisotropy is observed in the temperature range 25°∼400℃ and the maximum exists near 500℃. The second order of thermal expansion coefficient A and first order B are ?3.916×10?, ?3.685×10?, respectively. This results make good agreements with V.V.Zhdanova et al. in the comparable temperature range 25°∼200℃.

Application of moving particle simulation for the motion of a 2-D floating body with leaking oil in waves

정세민,남정우,박종천,윤상문,김성용,조용진 조선대학교 공학기술연구원 2018 공학기술논문지 Vol.11 No.1

In this study, the dynamic behaviors of a two-dimensional section of a floating body in waves are predicted using a modified particle-based method with a turbulence model. To predict the motion of a floating body, the free roll decay problem is simulated using the passively moving-solid model and the results are validated by comparing with the experiments. For the motion analysis on a floating body in waves, several types of cargo condition assumed to be partially-filled with solid and liquid cargos, such as water and oil, are simulated both with and without damage. As a result, the case loaded with liquid cargo showed more stable motion compared to the case with solid cargo. In addition, in the case with oil are damaged, the oil leak from the damaged part as well as the appearance of the leaked oil spilling towards inland sea are confirmed with a time lapse.

록인 증폭기에 의한 광전효과 실험

정세민 東亞大學校 大學院 1999 大學院論文集 Vol.24 No.-

It is known to us that photo-conductors reveal shot-noise in their operation and this kind of noise can be sucssesfully remove with the lock in amplifier(LIA) Because of the ability of the noise rejection in various circumstanes, the use of the LIA is more frequent than ever, Hence, we need to be farmiliar with the divice and operate skillfuly. For this purpose, author introduces a simple experiment using LIA, i.e. well known Photoelectric Effects. From the experimental result, it can be shown that the maximum energy of emitted photoelectrons is lying from 0.2eV to 0.3eV and the average energy is given by 0.43eV from the curve fitting. The maximum energy can be reasonably accepted from comparision with known data. Also from the fitting, it is found that the energy distribution would rather be a poissonian than maxwellian.

수술 위험도가 높은 담낭염에서의 담낭담관 스텐트 삽입술

정세민,김진남 대한내과학회 2023 대한내과학회 추계학술대회 Vol.2023 No.2

복합 가열 방식에 의한 구리증기 레이저의 제작

丁世敏 東亞大學校 大學院 1987 大學院論文集 Vol.12 No.-

An externally heated copper vapor laser system is a useful device for parametric studies of laser output since the discharge parameter can be controlled without interruption of the tube system. The operation temperature of the copper vapor laser is higher than 1000℃, thus the choice of the heating element is very limited. So, we adopt an hybrid type heating system, in which the kanthal A-1 is selected for an auxiliary heating-element. In this esperiment, the measured laser output power is 0.8W, the optimum temperature is 150 0℃, the optimum discharging rate is 5㎑

항공안전강화를 위한 연구

정세민,황정인,오현식,김학령 한국항공우주의학협회 2023 항공우주의학 학술대회 Vol.2023 No.11

Hydrophobic films for optical detection of dry carbon dioxide based on ion pairing and an amine polymer

정세민,이찬민,이준영,황기섭 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.6

Existing optical carbon dioxide sensors using ion pair materials with pH indicators need moisture to function. To sense dry carbon dioxide gas, hydrophobic films were prepared using an amine polymer (branched-polyethyleneimine)instead of water, along with an ion pair dye and an aromatic polymer. The color of the ion pair formedbetween cresol red sodium salt and tetra-n-octylammonium bromide was yellow when the pH was below neutral. After adding branched polyethyleneimine, the color changed to violet as the pH became basic. On exposure to carbondioxide, the amine groups on the branched-polyethyleneimine were converted to alkyl carbamate anions and ammoniumcations via reaction with the carbon dioxide. When the ion pair reacted with the resulting ammonium cations,the film changed color from violet to yellow. It was determined that the degree of color change was dependent on thecarbon dioxide exposure times and the amount of branched-polyethyleneimine added to the film.

강유전체 기억소자 응용을 위한 하부전극 최적화 연구

정세민,최유신,임동건,박영,송준태,이준식,Jung, S.M.,Choi, Y.S.,Lim, D.G.,Park, Y.,Song, J.T.,Yi, J. 한국결정성장학회 1998 한국결정성장학회지 Vol.8 No.4

본 논문은 PZT 박막의 기억소자 응용을 위한 Pt 그리고 RuO2 박막을 조사하였다. 초고주파 마그네트론 스퍼터링 방법을 이용하여 하부전극을 성장하였으며, 조사된 실험변수는 기판온도, 가스 부분압, RF 전력 그리고 후열처리 등이다. 기판온도는 Pt, $RuO_2$박막의 결정구조 뿐만 아니라 표면구조 및 비저항 성분에 크게 영향을 주었다. Pt 박막의 XRD 분석으로 기판온도가 상온에서 $200^{\circ}C$까지는 (111) 그리고 (200) 면이 혼재하는 결과를 보였으나 $300^{\circ}C$에서는 (111) 면으로 우선 방위 성장 특성을 보였다. XRD와 AFM 해석으로부터 Pt 박막 성장시 기판온도 $300^{\circ}C$, RF 전력 80W가 추천된다. 산소 분압비를 0~50%까지 가변하여 조사한 결과 산소가 5% 미만으로 공급되면 Ru 금속이 성장되고, 산소 분압비가 10 ~40%까지는 Ru와 $RuO_2$ 상이 공존하였으며 산소 분압비가 50%에서는 순수한 $RuO_2$상만이 검축되었다. 이 결과로부터 RuO2/Ru 이층 구조의 하부전극 형성이 산소 가스 부분압을 조절하여 한번의 공정으로 성장 가능하며, 이런 구조를 이용하면 금속의 낮은 비저항을 유지하면서도 PZT 박막의 산소 결핍에 의한 기억소자의 피로도 문제를 완화할 것으로 사료된다. 후 열처리 온도를 상온에서부터 $700^{\circ}C$까지 증가할 때 Pt와 $RuO_2$의 비저항 성분은 선형적 감소 추세를 보였다. 본 논문은 강유전체 기억소자 응용을 위한 최적화된 하부전극 제적조건을 제시한다. We have investigated Pt and $RuO_2$ as a bottom electrode for ferroelectric capacitor applications. The bottom electrodes were prepared by using an RF magnetron sputtering method. Some of the investigated parameters were a substrate temperature, gas flow rate, RF power for the film growth, and post annealing effect. The substrate temperature strongly influenced the surface morphology and resistivity of the bottom electrodes as well as the film crystallographic structure. XRD results on Pt films showed a mixed phase of (111) and (200) peak for the substrate temperature ranged from RT to $200^{\circ}C$, and a preferred (111) orientation for $300^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of $300^{\circ}C$ and RF power 80W for the Pt bottom electrode growth. With the variation of an oxygen partial pressure from 0 to 50%, we learned that only Ru metal was grown with 0~5% of $O_2$ gas, mixed phase of Ru and $RuO_2$ for $O_ 2$ partial pressure between 10~40%, and a pure $RuO_2$ phase with $O_2$ partial pressure of 50%. This result indicates that a double layer of $RuO_2/Ru$ can be grown in a process with the modulation of gas flow rate. Double layer structure is expected to reduce the fatigue problem while keeping a low electrical resistivity. As post anneal temperature was increased from RT to $700^{\circ}C$, the resistivity of Pt and $RuO_2$ was decreased linearly. This paper presents the optimized process conditions of the bottom electrodes for memory device applications.

디지털 오실로스코프에 의한 Wiener-Khinchin 정리의 시현

정세민,Jung, Se-Min 한국광학회 2013 한국광학회지 Vol.24 No.5

위너-킨친 정리(Wiener-Khinchin)는 어떤 신호의 자기상관 함수(Autocorrelation)가 그 신호의 일율 분광띠(Power Spectrum)에 해당됨을 보이는 것으로써, 분광학 및 통신 공학에서 신호 처리와 관련된 매우 중요한 정리이다. 학부 실험실에서 이 정리를 시현하려면 상관기(Correlator)와 신호 처리 장비와 같은 비교적 고가의 장비가 요구되므로, 정리의 시현이 용이하지 않다. 근래에 들어 디지털 공학의 발전과 함께 보급되고 있는 디지탈 오실로스코프들은 측정 결과의 수치화와 그들에 관한 연산 기능이 포함되어 있어, 이 정리를 간단히 시현시킬 수 있다. 본고에서는 정리의 유도 과정에서 얻어지는 실험 이론과 함께 디지털 오실로스코프를 이용해서 이 정리를 시현시키는 방법을 소개한다. 1930년대에 소개된 정리를 다시 재조명하려는 이유는, 비록 정리가 오래전에 소개되었다고는 할지라도 구체적인 유도 과정이나 물리 분야와 관련된 내용들은 우리에게는 여전히 잘 알려져 있지 않기 때문이다. 유도 과정에서 교류 복소 총저항(Impedence) Z, 역율(Power Factor), 위너 분광곡선의 확장된 물리적 의미와 함께, 나아가, 흑체 복사에서 플랑크(M. Planck)의 양자화에 대한 배경이 자연스럽게 나타나므로, 일반물리학, 현대물리학, 분광학 및 물성실험 등과 관련된 강의에 참고가 될 수 있다고 생각된다. The Wiener-Khinchin theorem, which means that the autocorrelation function of a signal corresponds to the power spectrum of the signal, is very important in signal processing, spectroscopy and telecommunications engineering. However, because of needs for some relatively expensive equipments such as a correlator and the signal processing system, its demonstration in most undergraduate class is not easy so far. Recently, digital oscilloscopes whose functions can be replaced foresaid equipments are marketed with development of digital engineering. In this paper, a simple demonstration of the theorem is given by a digital storage oscilloscope and a personal computer with its theoretical background. The reason that deals again with this theorem which has been introduced in 1930 is that it has been not well informed yet to us and theoretical background of the demonstration is directly introduced from its driving process. Through deriving process of the theorem, some extended physical meanings of the impedance, power, power factor, Wiener spectrum, linear system response and, furthermore, basic idea of the Planck's quantization in the black body theory reveal themselves naturally. Hence it can be referred to lectures in general physics, modern physics, spectroscopy and material characterization experiment.