Cycle-CVD법으로 증착된 TiN 박막의 ALD 증착기구와 특성에 관한 연구

민재식,손영웅,강원구,강상원,Min, Jae-Sik,Son, Young-Woong,Kang, Won-Gu,Kang, Sang-Won 한국재료학회 1998 한국재료학회지 Vol.8 No.5

Ti[N ($C_{2}$$H_{5}$ $CH_{3}$)$_{2}$]$_{4}$ [tetrakis(ethylmethylammino)titanium.TEMAT]와 $NH_{3}$를 반응가스로 하여 각각 펄스(pulse) 형태로 시분할 주입되는 새로운 박막 증착방법(이하 Cycle-CVD라 함)을 이용하여 TiN박막이 $SiO_2$.기판위에 증착되었다.Cycle-CVD에서 반을로 내로 주입되는 반응가스와 Ar가스는 TEAM 펄스, Ar 펄스,$NH_{3}$펄스, Ar 펄스의 순서로 시분할주입되었고, 이렇게 차례대로 주입되는 4개의 펄스를 하나의 cycle로 규정하고, Cycle-CVD는 이러한 cycle이 연속하여 반복적으로 주입되도록 설계되었다. 기판온도가 $170^{\circ}C$-$210^{\circ}C$에서는 atomic layer deposition(ALD)특성을 보였고, $200^{\circ}C$에서 충분한 반응가스의 펄스시간 후에 cycle당 증착된 박막의 두께가 0.6nm/cycle로 포화되는 양상을 보여주었는데, 이는 cycle당 증착된 TiN 박막의 두께가 1.6 monolayer(ML)/cycle에 해당된다. 이와 같이 반등가스의 흡착을 이용ㅇ하여 TiN이 제한된 표면반응만에 의하여 ALD 기구에 의해 증착이 이루어지므로 TiN 박막의 두께는 단지 cycle 횟수만으로 정확하게 제어할 수 있었고, 우수한 step coverage 특성을 얻었다. 또한 반응가스간의 기상반응을 방지함으로써 입자의 발생을 억제할 수 있었고, 상대적으로 낮은 온도임에도 불구하고 4at% 이하의 낮은 탄소함량을 갖는 양호한 특성을 보여주었다. Atomic layer deposition(ALD) of amorphous TiN films on $SiO_2$ between 17$0^{\circ}C$ and 21O$^{\circ}C$ has been investigated by alternate supply of reactant sources, Ti[N($C_2,H_5,CH_3)_2]_4$ [tetrakis(ethylmethylamminoltitanium: TEMAT] and $NH_3$. Reactant sources were injected into the reactor in the order of TEMAT vapor pulse, Ar gas pulse, $NH_3$. gas pulse and Ar gas pulse. Film thickness per cycle was saturated at around 1.6 monolayer(MU per cycle with sufficient pulse times of reactant sources at 20$0^{\circ}C$. The results suggest that film thickness per cycle could be beyond 1 MLicycie in ALD, which were explained by rechemisorption mechanisms of reactant sources. The ideal linear relationship be￢tween number of cycles and film thickness is confirmed. As a results of surface limited reactions of ALD, step cover￢age was excellent. Particles caused by the gas phase reactions between TEMAT and NH3 were almost free because TEMAT was seperated from $NH_3$ by the Ar pulse. In spite of relatively low substrate temperature, carbon impurity was incorporated below 4 at%.

열처리에 따른 CVD Cu 박막의 미세구조 및 전기 비저항의 변화

이원준(Won-Jun Lee),민재식(Jae-Sik Min),라사균(Sa-Kyun Rha),이영종(Young-Jong Lee),김우식(Woo-Sik Kim),김동원(Dong-Won Kim),박종욱(Chong-Ook Park) 한국진공학회(ASCT) 1995 Applied Science and Convergence Technology Vol.4 No.2

열처리에 따른 Cu 박막의 미세구조 및 전기 비저항의 변화를 조사하였다. Cu(hfac)(TMVS)를 원료로 하는 저압화학증착법에 의해 증착온도를 160℃에서 330℃까지 변화시키면서 TiN 기판 위에 Cu 박막을 제조하였고 450℃에서 30분간 열처리하였다. 증착온도에 따라 표면이 평평한 Cu 박막을 형성하는 표면 반응제한지역과 표면이 거친 Cu 박막을 형성하는 물질전달제한지역이 관찰되었다. 열처리 후 Cu 박막은 전체적으로 표면이 평탄해졌고 결정립의 크기는 모든 증착온도에서 증가하였는데 그 편차 역시 증가하여 EM 저항성 측면에서는 큰 효과를 보이지 못할 것으로 판단된다. 비저항은 증착온도 200℃에서 급격히 증가하였고 열처리 후에는 모든 증착온도에서 비저항이 감소하였는데 표면반응제한지역에서는 결정립 성장에 의한 약간의 비저항 감소를 보였으나 물질전달제한지역에서는 응집에 의해 Cu 결정립간의 전기적 연결 상태가 향상되어 급격한 비저항 감소를 보였다. The effects of the thermal annealing on the microstructure and the electrical resistivity of the copper films were studied. Copper film was prepared on TiN substrate by the low pressure chemical vapor deposition (LPCVD) using Cu(hfac)(TMVS) as the precursor at the deposition temperature between 160 and 330℃, and then annealed at 450℃ for 30 min. There were two distinct temperature regions, one is the surface reaction limited region, producing smooth surfaced copper film, and the other is the mass transport limited region which produces rough surfaced film. After annealing, the surfaces of the copper films had tendency to become smooth, and the grain size enlarged in all deposition temperature regions. However, the deviation of the grain size was increased too much to improve the EM resistance. The electrical resistivity showed a rapid increase at the deposition temperature of 200℃. After annealing, the resistivity of the copper film deposited in the surface reaction limited region decreased slightly by the grain growth, but ones deposited in the mass transport limited region decreased drastically by coalescence of the grains, causing the improvements of the electrical connections among copper grains.

한국에서 발생한 청천난류 사례들에 대한 수치연구

민재식(Jae-Sik Min),김정훈(Jung-Hoon Kim),전혜영(Hye-Yeong Chun) 한국기상학회 2012 대기 Vol.22 No.3

Generation mechanisms of the three moderate-or-greater (MOG)-level clear-air turbulence (CAT) encounters over South Korea are investigated using the Weather Research and Forecasting (WRF) model. The cases are selected among the MOG-level CAT events occurred in Korea during 2002-2008 that are categorized into three different generation mechanisms (upper-level front and jet stream, anticyclonic flow, and mountain waves) in the previous study by Min et al. For the case at 0127 UTC 18 Jun 2003, strong vertical wind shear (0.025 s?1) generates shearing instabilities below the enhanced upper-level jet core of the maximum wind speed exceeding 50 m s?1, and it induces turbulence near the observed CAT event over mid Korea. For the case at 2330 UTC 22 Nov 2006, areas of the inertia instability represented by the negative absolute vorticity are formed in the anticyclonically sheared side of the jet stream, and turbulence is activated near the observed CAT event over southwest of Korea. For the case at 0450 UTC 16 Feb 2003, vertically propagating mountain waves locally trigger shearing instability (Ri < 0.25) near the area where the background Richardson number is sufficiently small (0.25 < Ri < 1), and it induces turbulence near the observed CAT over the Eastern mountainous region of South Korea.

한국에서 발생한 청천난류 사례에서 나타나는 종관규모 대기상태에 대한 연구

민재식(Jae-Sik Min),전혜영(Hye-Yeong Chun),김정훈(Jung-Hoon Kim) 한국기상학회 2011 대기 Vol.21 No.1

The synoptic condition of clear-air turbulence (CAT) events occurred over South Korea is investigated, using the Regional Data Assimilation and Prediction System (RDAPS) data obtained from the Korea Meteorological Agency (KMA) and pilot reports (PIREPs) collected by Korea Aviation Meteorological Agency (KAMA) from 1 Dec. 2003 to 30 Nov. 2008. Throughout the years, strong subtropical jet stream exists over the South Korea, and the CAT events frequently occur in the upper-level frontal zone and subtropical jet stream regions where strong vertical wind shears locate. The probability of the moderate or greater (MOG)-level turbulence occurrence is higher in wintertime than in summertime, and high probability region is shifted northward across the jet stream in wintertime. We categorize the CAT events into three types according to their generation mechanisms: ⅰ) upper-level front and jet stream, ⅱ) anticyclonically sheared and curved flows, and ⅲ) breaking of mountain waves. Among 240 MOG-level CAT events reported during 2003-2008, 103 cases are related to jet stream while 73 cases and 25 cases are related to the anticyclonic shear flow and breaking of mountain wave, respectively.

지역예측모델 영역 크기에 따른 집중호우 수치모의 민감도 실험

민재식(Jae-Sik Min),노준우(Joon-Woo Roh),지준범(Joon-Bum Jee),김상일(Sangil Kim) 한국기상학회 2016 대기 Vol.26 No.1

In this study, we investigated the variabilities of wind speed of 850 hPa and precipitable water over the East Asia region using the NCEP Final Analysis data from December 2001 to November 2011. A large variance of wind speed was observed in northern and eastern China during the winter period. During summer, the regions of the East China Sea, the South Sea of Japan and the East Sea show large variances in the wind speed caused by an extended North Pacific High and typhoon activities. The large variances in the wind speed in the regions are shown to be correlated with the inter-annual variability of precipitable water over the inland region of windward side of the Korean Peninsula. Based on the investigation, sensitivity tests to the domain size were performed using the WRF model version 3.6 for heavy precipitation events over the Korean Peninsula for 26 and 27 July 2011. Numerical experiments of different domain sizes were set up with 5 km horizontal and 50 levels vertical resolutions for the control and the first experimental run, and 9 km horizontal for the second experimental run. We found that the major rainfalls correspond to shortwave troughs with baroclinic structure over Northeast China and extended North Pacific High. The correlation analysis between the observation and experiments for 1-h precipitation indicated that the second experiment with the largest domain had the best performance with the correlation coefficient of 0.79 due to the synoptic-scale systems such as short-wave troughs and North Pacific High.

해양혼합층 모델 적용을 통한 고해상도 지역예측모델 성능개선에 대한 연구

민재식(Jae-Sik Min),지준범(Joon-Bum Jee),장민(Min Jang),박정균(Jeong-Gyun Park) 한국기상학회 2017 대기 Vol.27 No.3

Ocean mixed layer (OML) depth affects diurnal cycle of sea surface temperature (SST) induced by change of solar radiation absorption and heat budget in ocean. The diurnal SST variation can lead to convection over the ocean, which can impact on localized precipitation both over coastal and inland. In this study, we investigate the OML characteristics affecting the diurnal cycle of SST for the Korean Peninsula and surrounding areas. To analyze OML characteristics, HYCOM oceanic mixed layer depth (MLD) and wind field at 10 m from ERAinterim during 2008~2016 are used. In the winter, MLD is deeply formed when the strong wind field is located on perpendicular to continental slope over deep seafloor areas. Besides, cooling SST-induced vertical mixing in OML is reinforced by dry cold air originated from Siberia. The OML in summer is shallowly distributed about 20 m. In order to estimate the impact of OML model in high resolution NWP model, four experimental simulations are performed. At this time, the prognostic scheme of skin SST is applied in NWP to simulate diurnal SST. The simulation results show that CNTL (off-OML) overestimates diurnal cycle of SST, while EXPs (on- OML) indicate similar results to observations. The prediction performance for precipitation of EXPs shows improvement compared with CNTL over coastal as well as inland. This results suggest that the application of the OML model in summer season can contribute to improving the prediction for performance of SST and precipitation over coastal area and inland.

모델 예측변수들을 이용한 집중호우 예측 가능성에 관한 연구

장민(Min Jang),지준범(Joon-Beom Jee),민재식(Jae-sik Min),이용희(Yong-Hee Lee),정준석(Jun-Seok Chung),유철환(Cheol-Hwan You) 한국기상학회 2016 대기 Vol.26 No.4

In order to determine the prediction possibility of heavy rainfall, a variety of analyses was conducted by using three-dimensional data obtained from Korea Local Analysis and Prediction System (KLAPS) re-analysis data. Strong moisture convergence occurring around the time of the heavy rainfall is consistent with the results of previous studies on such continuous production. Heavy rainfall occurred in the cloud system with a thick convective clouds. The moisture convergence, temperature and potential temperature advection showed increase into the heavy rainfall occurrence area. The distribution of integrated liquid water content tended to decrease as rainfall increased and was characterized by accelerated convective instability along with increased buoyant energy. In addition, changes were noted in the various characteristics of instability indices such as K-index (KI), Showalter Stability Index (SSI), and lifted index (LI). The meteorological variables used in the analysis showed clear increases or decreases according to the changes in rainfall amount. These rapid changes as well as the meteorological variables changes are attributed to the surrounding and meteorological conditions. Thus, we verified that heavy rainfall can be predicted according to such increase, decrease, or changes. This study focused on quantitative values and change characteristics of diagnostic variables calculated by using numerical models rather than by focusing on synoptic analysis at the time of the heavy rainfall occurrence, thereby utilizing them as prognostic variables in the study of the predictability of heavy rainfall. These results can contribute to the identification of production and development mechanisms of heavy rainfall and can be used in applied research for prediction of such precipitation. In the analysis of various case studies of heavy rainfall in the future, our study result can be utilized to show the development of the prediction of severe weather.

PS강봉에 의한 단경간 강상자형 합성보의 선압축 효과

구민세(Koo Min Se),이호경(Lee Ho Kyoung),민재식(Min Jae Sik) 대한토목학회 2000 대한토목학회 학술발표회 논문집 Vol.2000 No.1

학생 능동수업의 교육적 효과에 대한 초ㆍ중ㆍ고등학교 학생들의 인식

최윤희(Choi, YunHee),김용진(Kim, Yong-Jin),민재식(Min, Jae Sik),이윤형(Lee, Yoonhyeong),한효정 (Han, Hyojeong),김미점(Kim, Mi Jeom),이동엽(Lee, Dong Yup),신영준(Shin, Youngjoon) 학습자중심교과교육학회 2018 학습자중심교과교육연구 Vol.18 No.5

본 연구는 학생 능동 수업 유형과 학생 능동 수업의 교육적 효과에 대한 초ㆍ중ㆍ고등학생들의 인식을 살펴본 것이다. 본 연구는 2016년 7월부터 12월까지 수행되었다. 연구 참여자로는 학생 능동수업의 경험을 가진 초ㆍ중ㆍ고등학교 학생 460명을 대상으로 진행하였다. 연구 결과를 살펴보며, 본 연구를 위해 학생 능동수업 성과 지표를 개발하고, 학생 능동수업 유형별 교육적 효과 차이와 학생 능동수업의 교육적 효과에 대한 인식 차이를 분석하였다. 첫째, 언어적인 활동이 중심이 되는 수업보다 는 학생들은 조작적이며 수공적인 유형의 수업에서 학생 능동 수업의 효과가 높게 나타났다. 고등학생보다는 초ㆍ중학생이, 여학생보다는 남학생이, 학업 성적은 중, 하 수준의 학생보다 상 수준의 학생들이 능동 수업의 모든 유형에서 높은 효과가 나타났다. 6개월에서 1년 미만 능동 수업 경험을 가진 경우에 학생 능동 수업의 교육적 효과가 높게 나타났다. 둘째, 학생 능동 수업의 교육적 효과에서는 모든 영역에서 고르게 높게 나타났다. 그러나, ‘과학적 사고력’, ‘자기 주도 학습 능력’, ‘정보 매체 활용 능력’,‘발표 토론 참여 빈도 증가’ 부분에서는 효과가 나타나지 않는다는 인식이 많았다. 학교급별 효과 차이는 ‘심미적 감성 역량’, ‘자기 관리 역량’, ‘과학적 참여’, ‘자기 주도 학습 시간의 증가’ 부분에서 중학생들의 효과가 초등, 고등학생들에 비해 크게 나타났다. ‘과학적 사고력’, ‘자기관리’, ‘과학적 참여’ 부분에서는 남학생에게 효과가 있었고, 1년 이상 학생 능동 수업을 받은 학생들은 ‘자기 주도 학습 시간의 증가’ 면에서 효과가 크게 나타났다. 따라서, 학생들의 학업 성적과 능동 수업의 경험에 따른 학생들의 잠재적인 발달 수준의 간격을 줄일 수 있는 방안 제시와 학교급별, 성별에 따른 학생 능동수업의 교육적 효과에 대한 차이가 나타나는 원인을 양적 및 질적 분석을 통해 좀 더 심도 깊게 밝히고 구체적인 대안의 마련이 필요하다. This study examined the perceptions of elementary, middle and high school students on the educational effects of student active class types and student active classes. This study was conducted from July to December, 2016. Participants were 460 elementary, midddle, and high school students with active experience in student activities. As a result, first, students active classroom activities were more effective than active classroom activities. The results of this study were as follows. First, the students with high academic achievement were more effective in all types of active class than the students with middle and lower grades. In the case of students who have active class experience for 6 months to less than 1 year, the active effect of student active class is high. Second, the educational effect of student active class was e enly higher in all areas. Howe er, there were many perceptions that scientific thinking , self-directed learning ability , ability to use information media , and The effect of school level difference on the effect of middle school students on aesthetic emotional competence , self-management competency , scientific participation , and increase of self-directed learning time was higher than that of elementary and high school students. Scientific thinking , Self-management , and Scientific participation were effective for male students, and students who received active classes for more than one year were more effective in increasing self-directed learning time. Therefore, it is important to identify ways to reduce the gap between the student s potential developmental level and the educational effect of active classroom activities, depending on the school s grade and gender, It is necessary to clarify more deeply through the analysis and to prepare specific alternatives.

수도권지역의 지표이용도 및 인공열 상세적용에 따른 고해상도 수치실험 연구

이한경 ( Hankyung Lee ),지준범 ( Joon-bum Jee ),민재식 ( Jae-sik Min ) 한국농림기상학회 2017 한국농림기상학회지 Vol.19 No.4

본 연구에서는 지표이용도 특성이 반영된 고해상도 기상예측모델 도시캐노피모형(WRF-UCM)의 수치모의 실험을 통해 도심과 전원 지역 기상변수 및 에너지수지 변화 경향에 대하여 분석하였다. UCM을 적용하지 않은 WRF 모의 결과를 규준실험으로 설정하였으며, 거칠기 길이 변화와 인공열 고려에 따라 총 4가지 실험을 비교하여 분석하였다. UCM을 적용한 실험에서 거칠기 길이의 수정 전과 후의 기온과 풍속의 변화가 크게 나타나지 않았으나, 인공열을 고려한 UCM의 모의 기온과 풍속은 고려하기 전보다 크게 차이가 나타났다. 모의 실험 간의 차이는 전원 지역보다 도시지역에서 더 크게 나타났다. 자동기상관측(AWS) 기온 관측 자료에 대하여 UCM에 인공열을 고려한 결과의 평방근오차(RMSE)가 가장 적었다. 또한, 차세대도 시농림융합기상사업단의 중랑 에너지수지관측소지점의 현열플럭스 관측자료에 대한 검증 수치는 인공열을 고려하여 UCM을 적용한 실험의 RMSE와 BIAS 값이 가장 낮았다. 인공열을 고려한 UCM 적용이 도심의 현열플럭스 모의 향상에 영향을 주었다. 또한, UCM을 적용한 후 도시 지역 잠열플럭스의 변화 모의를 분석할 수 있었으며, 도심과 전원 지역 모두 UCM 적용후에 관측 값과 더 가까운 검증 수치를 나타냈다. 결과적으로 WRF 모델에 UCM의 적용이 지표플럭스 모의 향상에 기여하는 것으로 나타났다. In this study, the high-resolution numerical simulation results considering landuse characteristics are analyzed by using single layer Urban Canopy Model (UCM) in Weather Research Forecast (WRF). For this, the impact of urban parameters such as roughness length and anthropogenic heat in UCM is analyzed. These values are adjusted to Seoul metropolitan area in Korea. The results of assessment are verified against observation from surface and flux tower. Forecast system equipped with UCM shows an overall improvement in the simulations of meteorological parameters, especially temperature at 2 m, surface sensible and latent heat flux. Major contribution of UCM is appreciably found in urban area rather than non-urban. The non-urban area is indirectly affected. In simulated latent heat flux, applying UCM is possible to simulate the change similarly with observations on urban area. Anthropogenic heat employed in UCM shows the most realistic results in terms of temperature and surface heat flux, indicating thermodynamic treatment of UCM could enhance the skills of high resolution forecast model in urban and non-urban area.