RF 스퍼터링을 이용하여 저온에서 SiO₂/Si 기판 위에 증착된 La_0.7Sr_0.3MnO₃ 박막의 구조 및 전기적 특성

최선규,하태정,유병곤,박영호,Choi, Sun-Gyu,Reddy, A. Sivasankar,Ha, Tae-Jung,Yu, Byoung-Gon,Park, Hyung-Ho 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.11

The $La_{0.7}Sr_{0.3}MnO_3$ was deposited on $SiO_2/Si$ substrate by RF magnetron sputtering. The oxygen gas flow rate was changed from 0 to 80 sccm and the substrate temperature was $350^{\circ}C$. The oxygen gas flow rate was changed to control the growth orientation and crystalline state of the film. Relatively high TCR (temperature coefficient of resistance) value (-2.33%/K) was obtained when comparing with the reported values of the films prepared by using high substrate anneal temperature. The decrease in the sheet resistance and TCR value were observed when grain size of the film increased with the increase of oxygen gas flow rate.

SiO₂/Si 및 Si 기판에 rf magnetron sputtering법으로 증착된 적외선 센서용 La_0.7Sr_0.3MnO₃ CMR 박막 저항체 특성연구

최선규,유병곤,류호준,박형호,Choi, Sun-Gyu,Reddy, A. Sivasankar,Yu, Byoung-Gon,Ryu, Ho-Jun,Park, Hyung-Ho 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.2

$La_{0.7}Sr_{0.3}MnO_3$ 박막을 rf 마그네트론 스퍼터를 이용하여 챔버 내 산소가스유량비를 0, 40, 80 sccm 으로 조절하고 후열처리 공정 없이 기판온도를 $350^{\circ}C$로 유지하면서 $SiO_2$/Si(100) 및 Si(100) 기판에 증착하였다. 증착된 $La_{0.7}Sr_{0.3}MnO_3$ 박막은 $SiO_2$/Si(100), Si(100) 기판 모두 (100), (110), (200)면을 갖는 polycrystalline 상태였으며, oxygen flow rate이 증가함에 따라 박막의 grain size가 증가하였다. 증가되는 grain size로 인하여 grain boundary가 감소하였고 따라서 높은 oxygen flow rate에서 증착된 박막은 면저항이 감소하는 현상을 나타내었다. $SiO_2$/Si 기판과 Si 기판에 증착된 LSMO 박막의 TCR 값은 약 -2.0 $\sim$ -2.2%를 나타내었다. $La_{0.7}Sr_{0.3}MnO_3$ films were deposited on $SiO_2$/Si and Si substrates annealed at $350^{\circ}C$ by rf magnetron sputtering. The oxygen gas flow rates were varied as 0, 40, and 80 sccm. Without post annealing process, $La_{0.7}Sr_{0.3}MnO_3$ thin films on $SiO_2$/Si and Si substrates were polycrystalline with (100), (110), and (200) growth planes. The grain size of $La_{0.7}Sr_{0.3}MnO_3$ thin films was increased with increasing oxygen gas flow rate. The sheet resistance of $La_{0.7}Sr_{0.3}MnO_3$ thin films was decreased with oxygen flow rate due to the increased grain size which induced a reduction of grain boundary. TCR (temperature coefficient of resistance) values of $La_{0.7}Sr_{0.3}MnO_3$ thin films were obtained from -2.0% to -2.2%.

충청도(忠淸道) 일원(一圓)의 금(金)·은(銀)광상(鑛床)에 대한 광물학적(鑛物學的) 연구(硏究)

최선규,박노영,홍세선,Choi, Seon Gyu,Park, No Young,Hong, Sei Sun 대한자원환경지질학회 1988 자원환경지질 Vol.21 No.3

A large number of gold and/or silver-bearing quartz veins occur in or near Mesozoic granite batholith elongated in a NE-SW direction within the Chungcheong Province. Precambrian schists and gneisses, and Jurassic and Cretaceous granitic rocks serve as hosts for gold and/or silver deposits. On the basis of Ag/Au total production and ore grade ratio, 15 mines may be divided into three major groups: gold-dominant deposits, gold-silver deposits, and silver-dominant deposits. The chemical composition of electrum from skarn deposit (Geodo mine), alaskite-type deposit (Geumjeong mine) and 15 vein deposits was summarized. It was found that the Au content of electrum for vein deposits ranging from 5.2 to 86.5 is lower than that for skarn and alaskite deposits. Among 15 vein deposits, the composition of electrum associated with pyrrhotite is relatively high and has a narrow range of 40.8 to 86.5 atomic % Au, but the Au content of electrum with pyrite is in range of 5.2 to 82.8 atomic %, and is clearly lower than that with pyrrhotite. The grouping of ages for these mines indicates that gold and/or silver mineralizations occurred during two periods in the Mesozoic. Daebo igneous activities are restricted to gold mineralization in the range of 158 to 133 Ma, whereas Bulgugsa igneous activities are related to gold and/or silver mineralization ranging from 108 to 71 Ma. Generally speaking, Jurassic gold-dominant veins have many common characteristics; notably prominent association with pegmatites, simply massive vein morphology, high fineness in the ore concentrates, rarity of silver minerals, and a distinctively simple mineralogy, including sphalerite, galena, chalcopyrite, pyrrhotite and/or pyrite. Although individual deposits exhibit widely differing diversity, Cretaceous gold-silver and silver-dominant veins are characterized by features such as complex vein, low to medium fineness in the ore concentrates and abundance of silver minerals including Ag sulfosalts, Ag sulfides, Ag tellurides and native silver.

한국의 급경사지 붕괴 예 · 경보 시스템 개발 현황

최선규(Choi, Sun Gyu),김호종(Kim, Ho Jong) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10

변위 기반의 급경사지 붕괴에 대한 주민대피 권고기준 제안

최선규(Choi, Sun Gyu),정향선(Jeong, Hyang Seon),석재욱(Suk, Jae Wook),강효섭(Kang, Hyo Sub),송효성(Song, Hyo Sung) 대한토목학회 2020 대한토목학회 학술대회 Vol.2020 No.10

SiO₂/Si 및 Si 기판에 rf magnetron sputtering법으로 증착된 적외선 센서용 La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>MnO₃ CMR 박막 저항체 특성연구

최선규(Sun Gyu Choi),A. Sivasankar Reddy,유병곤(Byoung-Gon Yu),류호준(Hojun Ryu),박형호(Hyung-Ho Park) 한국진공학회(ASCT) 2008 Applied Science and Convergence Technology Vol.17 No.2

La0.7Sr0.3MnO₃ 박막을 rf 마그네트론 스퍼터를 이용하여 챔버 내 산소가스유량비를 0, 40, 80 sccm 으로 조절하고 후열처리 공정 없이 기판온도를 350℃로 유지하면서 SiO₂/Si(100) 및 Si(100) 기판에 증착하였다. 증착된 La0.7Sr0.3MnO₃ 박막은 SiO₂/Si(100), Si(100) 기판 모두 (100), (110), (200)면을 갖는 polycrystalline 상태였으며, oxygen flow rate이 증가함에 따라 박막의 grain size가 증가하였다. 증가되는 grain size로 인하여 grain boundary가 감소하였고 따라서 높은 oxygen flow rate에서 증착된 박막은 면저항이 감소하는 현상을 나타내었다. SiO₂/Si 기판과 Si 기판에 증착된 LSMO 박막의 TCR 값은 약 -2.0 ~ -2.2%를 나타내었다. La0.7Sr0.3MnO₃ films were deposited on SiO₂/Si and Si substrates annealed at 350℃ by rf magnetron sputtering. The oxygen gas flow rates were varied as 0, 40, and 80 sccm. Without post annealing process, La0.7Sr0.3MnO₃ thin films on SiO₂/Si and Si substrates were polycrystalline with (100), (110), and (200) growth planes. The grain size of La0.7Sr0.3MnO₃ thin films was increased with increasing oxygen gas flow rate. The sheet resistance of La0.7Sr0.3MnO₃ thin films was decreased with oxygen flow rate due to the increased grain size which induced a reduction of grain boundary. TCR (temperature coefficient of resistance) values of La0.7Sr0.3MnO₃ thin films were obtained from -2.0% to -2.2%.

다수준 분석을 통한 팀 특성과 개인 창의성 간 관계에 관한 연구: 팀 수준의 심리적 안전감과 실수관리 스타일 중심으로

최선규(Choi, Sun-Gyu),지성구(Ji, Seong-Goo) 한국인사관리학회 2016 조직과 인사관리연구 Vol.40 No.3

창의성은 조직의 성공을 결정하는 핵심적인 요소로 강조되어 왔으며, 그에 따라 조직 구성원의 창의성을 어떻게 발현시킬 것인가 하는 문제는 조직행동 분야에서 매우 중요한 주제로 다루어져왔다. 창의성에 영향을 미치는 다양한 요인들 중에서, 본 연구는 팀 수준의 팀 심리적 안전감과 실수관리 스타일을 중심으로 개인 창의성에 미치는 영향을 다수준 분석을 활용하여 분석하였다. 팀 구성원의 창의성은 자신의 아이디어를 편안하게 표현할 수 있는 환경과 업무수행 과정에서 발생하는 실수를 단순한 과실이 아니라 창의적인 대안을 제공하는 기회로 인식하는 것이 무엇보다 중요하기 때문이다. 이를 위해 다양한 산업군에 분포되어 있는 57개의 팀, 235명의 응답자를 대상으로 수집한 자료를 분석해 활용하였다. 분석결과, 팀의 심리적 안전감은 개인 창의성과 정(+)의 관계를 갖는 것으로 나타났다. 그리고 팀의 실수해결 스타일 역시 개인 창의성과 정(+)의 관계를 가지는 것으로 나타난 반면, 실수비난 스타일은 예상과 달리 개인 창의성과는 통계적으로 유의하지 않은 관계를 갖는 것으로 나타났다. 이러한 결과를 통해 팀 구성원의 창의성 발현을 장려하고 촉진하기 위해서는 구성원들이 자신의 아이디어나 의견을 심리적으로 편안하며 안전하게 표현할 수 있는 팀 환경을 조성할 필요가 있다. 이와 함께, 업무과정에서 발생하는 실수를 복잡한 문제를 해결하며 창의적인 대안을 획득하는 효과적인 방법으로 인식할 필요성을 제시한다. Creativity has been emphasized as one of the key determinants of organizational success. For this reason, the issue of how to lead employees’ creativity has been treated with great importance in the field of organizational behavior. Among many other factors that can affect employees’ creativity, this study utilizes multilevel analysis to focus on the impact of psychological safety and mistake management styles in team contexts. The creative behavior of individuals in a team depends on a comfortable working environment where employees can freely express their ideas, and where mistakes do not lead solely to blame, but are recognized as opportunities to suggest creative alternatives. To test the proposed research hypotheses, this study uses empirical data collected from 57 teams consisting of 235 full-time employees working in the manufacturing, service, and financial sectors. Results, based on a survey of team members, revealed that psychological safety was positively correlated with employee creativity. We also found that a mistake-solving style was positively correlated with employee creativity, while a mistake-blaming style was not significantly correlated with employee creativity. These results suggest that in order to facilitate and encourage employee creativity, it is necessary to foster a team environment where employees feel comfortable and psychologically safe in expressing their ideas and opinions. Mistakes in the work process can be perceived as an effective means of achieving creative solutions and resolving complex problems.

상사의 행동특성이 구성원의 심리적 안전감, 침묵과 친사회적 발언행동에 미치는 영향

최선규(Choi, Sun Gyu),지성구(Ji, Seong Goo) 한국인사관리학회 2012 조직과 인사관리연구 Vol.36 No.4

본 연구는 상사의 행동특성이 구성원의 심리적 안전감, 침묵행동과 친사회적 발언행동에 어떠한 영향을 미치는지를 연구하기 위한 것이다. 구체적으로 상사의 행동특성을 협동적 행동, 경쟁적 행동, 그리고 개인주의적 행동으로 구분하고 각각의 행동특성이 심리적 안전감에 미치는 영향을 조사하였다. 그리고 심리적 안전감이 구성원의 침묵행동과 친사회적 발언행동에 어떠한 영향을 미치는지를 연구하였다. 또한 이들 관계에서 심리적 안전감의 매개효과를 함께 연구하였다. 설정된 연구모형과 가설을 검증하기 위해 제조업과 서비스기업에 근무하는 조직구성원 204명을 대상으로 실증분석을 실시하였다. 연구결과를 살펴보면, 상사의 행동특성 중 협동적 행동은 심리적 안전감에 정(+)의 영향을 미치는 것으로 나타났으며, 경쟁적 행동은 심리적 안전감에 부(-)의 영향을 미치는 것으로 나타난 반면, 개인주의적 행동은 예상과 달리 심리적 안전감에 정(+)의 영향을 미치는 것으로 나타났다. 그리고 심리적 안전감은 구성원의 침묵행동에는 부(-)의 영향을, 친사회적 발언행동에는 정(+)의 영향을 미치는 것으로 밝혀졌다. 또한 구성원의 심리적 안전감은 상사의 행동특성과 침묵행동, 친사회적 발언행동 사이에서 매개역할을 하는 것으로 나타났다. 이러한 결과를 통해 구성원이 지각하는 상사의 행동특성은 심리적 안전감에 영향을 미치는 요인으로 확인되었다. 그리고 심리적 안전감은 구성원이 업무나 조직에 관련된 아이디어, 의견 등을 의도적으로 표현하지 않고 억제하거나 혹은 적극적으로 의견을 표현할 것인지를 결정하는 요인으로 나타났다. 마지막으로 본 연구결과를 토대로 연구의 시사점과 한계, 그리고 향후 연구 과제를 제시하였다. The purpose of this study is the impact of supervisor’s behavior on the psychological safety, employee silence, and prosocial voice. Specifically, we examined relationships between the supervisor behaviors: cooperative, competitive, and individualistic and psychological safety, respectively. And, we examined the impact of psychological safety on silence and prosocial voice. Also we examined the mediating effect of psychological safety between supervisor’s behavior and two outcome variables To test the proposed research model and hypotheses, empirical data was collected from 204 full-time employees working manufactures, information technology company. Results indicate supervisor’s cooperative behavior was positive relations with psychological safety, while competitive behavior was negative effects on psychological safety. Contrary to hypothesis, supervisor’s individualistic behavior was positively associated with psychological safety. Results also showed that, while psychological safety was positively related to prosocial voice, it was negatively related to silent behavior. Also, we found statistically significant mediating effects of psychological safety for silent behavior and prosocial voice behavior. We discuss the implications of these of findings for both theory and practice.

반도체 노광 공정의 DI 세정과 Oxide의 HF 식각 과정이 실리콘 표면에 미치는 영향

백정헌,최선규,박형호,Baik, Jeong-Heon,Choi, Sun-Gyu,Park, Hyung-Ho 한국재료학회 2010 한국재료학회지 Vol.20 No.8

This study shows the effects of deionized (DI) rinse and oxide HF wet etch processes on silicon substrate during a photolithography process. We found a fail at the wafer center after DI rinse step, called Si pits, during the fabrication of a complementary metal-oxide-semiconductor (CMOS) device. We tried to find out the mechanism of the Si pits by using the silicon wafer on CMOS fabrication and analyzing the effects of the friction charge induced by the DI rinsing. The key parameters of this experiment were revolution per minute (rpm) and time. An incubation time of above 10 sec was observed for the formation of Si pits and the rinsing time was more effective than rpm on the formation of the Si pits. The formation mechanism of the Si pits and optimized rinsing process parameters were investigated by measuring the charging level using a plasma density monitor. The DI rinse could affect the oxide substrate by a friction charging phenomenon on the photolithography process. Si pits were found to be formed on the micro structural defective site on the Si substrate under acceleration by developed and accumulated charges during DI rinsing. The optimum process conditions of DI rinse time and rpm could be established through a systematic study of various rinsing conditions.

저유전물질로의 응용을 휘한 규칙성 메조포러스 실리카 박막에의 HMDS 처리

하태정,최선규,유병곤,박영호,Ha, Tae-Jung,Choi, Sun-Gyu,Yu, Byoung-Gon,Park, Hyung-Ho 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.1

In order to reduce signal delay in ULSI, an intermetal material of low dielectric constant is required. Ordered mesoporous silica film is proper to intermetal dielectric due to its low dielectric constant and superior mechanical properties. The ordered mesoporous silica film prepared by TEOS (tetraethoxysilane) / MTES (methyltriethoxysilane) mixed silica precursor and Brij-76 surfactant was surface-modified by HMDS (hexamethyldisilazane) treatment to reduce its dielectric constant. HMDS can substitute $-Si(CH_3)_3$ groups for -OH groups on the surface of silica wall. In order to modify interior silica wall, HMDS was treated by two different processes except the conventional spin coating. One process is that film is dipped and stirred in HMDS/n-hexane solution, and the other process is that film is exposed to evaporated HMDS. Through the investigation with different HMDS treatment, it was concluded that surface modification in evaporated HMDS was more effective to modify interior silica wall of nano-sized pores.