• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1269-1280
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• 2009

This study was performed to construct sound performance DB of royal palace buildings and to examine the special quality more scientifically. Research target of royal palace were Changdeokgung and Gyeongbokgung. Sound insulation performance between the adjacent room and facade, room acoustics of Pyeonjeon and Chimjeon which is representative building in royal palace were examined through field measurement. Measured values of RT($T_{mf}$) at Pyeonjeon were 0.78 sec. and 1.03 sec. in Seonjeongjoen and Sajeongjoen, respectively. The RTs of both Pyeonjeon buildings were estimated suitable for speech and lecture considering their volume. The RT($T_{mf}$)s at Chimjeon were measured in range of 0.29~0.55 sec. This meant that the acoustic energy in rooms was decreased by sound transmission through mulberry paper(Hanji) of traditional windows and doors. As a sound insulation performance, the single-number quantities($D_{ls,2m,nT,w}$) of the building facades in Pyeonjeon and Chimjeon were measured 4~20 dB. Also the single-number quantities($D_{p,w}$) between the adjacent rooms in Chimjeon were measured 3~18 dB. Sound insulation performance of traditional building elements such as window and door depended strongly on their layers and area.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.210-210
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• 2011

The effects of CH2F2 and N2 gas flow rates on the etch selectivity of silicon nitride (Si3N4) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si3N4 pattern were investigated during etching of a Si3N4/EUV resist structure in dual-frequency superimposed CH2F2/N2/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH2F2 and N2 gases played a critical role in determining the process window for ultra-high etch selectivity of Si3N4/EUV resist due to disproportionate changes in the degree of polymerization on the Si3N4 and EUV resist surfaces. Increasing the CH2F2 flow rate resulted in a smaller steady state CHxFy thickness on the Si3N4 and, in turn, enhanced the Si3N4 etch rate due to enhanced SiF4 formation, while a CHxFy layer was deposited on the EUV resist surface protecting the resist under certain N2 flow conditions. The LER values of the etched resist tended to increase at higher CH2F2 flow rates compared to the lower CH2F2 flow rates that resulted from the increased degree of polymerization.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.35-38
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• 2002

In this paper, the characteristics of channel hot electron (CHE) injection for the write operation in a NOR-type SONOS flash memory with common source line were investigated. The thicknesses of he tunnel oxide, the memory nitride， and the blocking oxide layers for the gate insulator of the fabricated SONOS devices were $34{\AA}$, $73{\AA}$, and $34{\AA}$, respectively. The SONOS devices compared to floating gate devices have many advantages, which are a simpler cell structure, compatibility with conventional logic CMOS process and a superior scalability. For these reasons, the introduction of SONOS device has stimulated. In the conventional SONOS devices, Modified Folwer-Nordheim (MFN) tunneling and CHE injection for writing require high voltages, which are typically in the range of 9 V to 15 V. However CHE injection in our devices was achieved with the single power supply of 5 V. To demonstrate CHE injection, substrate current (Isub) and one-shot programming curve were investigated. The memory window of about 3.2 V and the write speed of $100{\mu}s$ were obtained. Also, the disturbance and drain turn-on leakage during CHE injection were not affected in the SONOS array. These results show that CHE injection can be achieved with a low voltage and single power supply, and applied for the high speed program of the SONOS memory devices.

• 한국재료학회지
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• 제17권2호
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• pp.73-80
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• 2007

For the sub-65 nm CMOS process, it is necessary to develop a new silicide material and an accompanying process that allows the silicide to maintain a low sheet resistance and to have an enhanced thermal stability, thus providing for a wider process window. In this study, we have evaluated the property and unit process compatibility of newly proposed composite silicides. We fabricated composite silicide layers on single crystal silicon from $10nm-Ni_{1-x}Co_x/single-crystalline-Si(100),\;10nm-Ni_{1-x}Co_x/poly-crystalline-\;Si(100)$ wafers (x=0.2, 0.5, and 0.8) with the purpose of mimicking the silicides on source and drain actives and gates. Both the film structures were prepared by thermal evaporation and silicidized by rapid thermal annealing (RTA) from $700^{\circ}C\;to\;1100^{\circ}C$ for 40 seconds. The sheet resistance, cross-sectional microstructure, surface composition, were investigated using a four-point probe, a field emission scanning probe microscope, a field ion beam, an X-ray diffractometer, and an Auger electron depth profi1ing spectroscopy, respectively. Finally, our newly proposed composite silicides had a stable resistance up to $1100^{\circ}C$ and maintained it below $20{\Omega}/Sg$., while the conventional NiSi was limited to $700^{\circ}C$. All our results imply that the composite silicide made from NiCo alloy films may be a possible candidate for 65 nm-CMOS devices.

• 전기학회논문지
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• 제65권12호
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• pp.2014-2018
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• 2016

Transparent, conductive electrode films, showing the particular characteristics of good conductivity and high transparency, are of considerable research interest because of their potential for use in opto-electronic applications, such as smart window, photovoltaic cells and flat panel displays. Multilayer transparent electrodes, having a much lower electrical resistance than widely-used transparent conducting oxide electrodes, were prepared by using RF/DC magnetron sputtering system. The multilayer structure consisted of three layers, [NiInZnO(NIZO)/Ag/NIZO]. The optical and electrical properties of the multilayered NIZO/Ag/NIZO structure were investigated in relation to the thickness of each layer. The optical and electrical characteristics of multilayer structures have been investigated as a function of the Ag and NIZO film thickness. High-quality transparent conductive films have been obtained, with sheet resistance of $9.8{\Omega}/sq$ for Ag film thickness of 8 nm. Also the multilayer films of inserted Ag 8 nm thickness showed a high optical transmittance above 93% in the visible range. The electrical and optical properties of the new multilayer films were mainly dependent on the thickness of Ag insertion layer.

• 한국재료학회지
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• 제12권1호
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• pp.36-43
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• 2002

In this study, the nanosized ZnS thin films that can be used for fabrication of blue light-emitting diodes, electro-optic modulators, and n-window layers of solar cells were grown by the solution growth technique (SGT), and their surface morphology and film thickness and grain size dependence on the growth conditions were examined. Based on these results, the quantum size effects of ZnS were systematically investigated. Governing factors related to the growth condition were the concentration of precursor solution, growth temperature, concentration of aq. ammonia, and growth duration. X-ray diffraction patterns showed that the ZnS thin film obtained in this study had the cubic structure ($\beta$-ZnS). With decreasing growth temperature and decreasing concentration of precursor solution, the surface morphology of film was found to be improved. Also, the film thickness depends largely on the ammonia concentration. In particular, this is the first time that the surface morphology dependence of ZnS film grown by SGT on the ammonia concentration is reported. The energy band gaps of samples were determined from the optical transmittance values, and were shown to vary from 3.69 eV to 3.91 eV. These values were substantially higher than 3.65 eV of bulk ZnS. It was also shown that the quantum size effect of SGT grown ZnS is larger than that of the ZnS films grown by most other growth techniques.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.676-684
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• 2020

This study was carried out in order to evaluate the bending creep deflection of glulams and bolted glulams beam-to-beam connection with steel-gusset plates and bolts under changing relative humidity. The two types of glulam beams (130 mm in width, 175 mm in thickness, and 3000 mm in length) used in this study were made from domestic larch and composed of seven layers. The gussets were made of 8-mm-thick steel plates. Creep testing was conducted under constant loads in an uncontrolled environment. The test was carried out in a room that was well ventilated through a window. The creep test specimens were loaded for 33,000 hours. A bending creep test for the glulams was conducted through four-point loading. The applied stresses were 20% and 30% of the MOR in the static bending test for the glulam and bolted glulam, respectively. After 33,000 hours, the creep deflection of the glulam at a 20% stress level increased by 39% to 99%, while the creep deflection of the glulam at a 30% stress level increased by 27% to 67%, as compared with instantaneous elastic deflection. The relative creep increased during autumn and winter, and recovered during spring and summer. The relative creep of the bolted glulams was changed abruptly by loading up to 5,000 hours, but stabilized after 5,000 hours, and then gradually increased until 33,000 hours. The relative creep of the bolted glulam increased 2.11 times on average after 33,000 hours.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.9-10
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• 2010

Since the discovery of graphene by mechanical exfoliation from graphite[1], various fabrication methods are available today such as chemical exfoliation, epitaxial graphene on SiC substrates, etc. In view of industrialization, the mechanical exfoliation method may not be an option. Epitaxial graphene on SiC substrates, in this respect, is by far more practical because the method consists of conventional thermal treatments familiar to semiconductor industry. Still, the use of the SiC substrate itself, and hence the incompatibility with the Si technology, lessens the importance of this technology in its future industrialization. In this context, we have tackled the problem of forming graphene on Si substrates (GOS). Our strategy is to form an ultrathin (~80 nm) SiC layer on top of a Si substrate, and to graphitize the top SiC layers by a vacuum annealing. We have actually succeeded in forming the GOS structure [2,3,4]. Raman-scattering microscopy indicates presence of few-layer graphene (FLG) formed on our annealed SiC/Si heterostructure, with the G ($1580\;cm^{-1}$) and the G'($2700\;cm^{-1}$) bands, both related to ideal graphene, clearly observed. Presence of the D ($1350\;cm^{-1}$) band indicates presence of defects in our GOS films, whose elimination remains as a challenge in the future. To obtain qualified graphene films on Si substrate, formation of qualified SiC films is crucial in the first place, and is achieved by tuning the growth parameters into a process window[5]. With a potential for forming graphene films on large-scale Si wafers, GOS is a powerful candidate as a key technology in bringing graphene into silicon technology.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.291-291
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• 2013

The interior vehicle noise due to the exterior aerodynamic field is an important topic in the acoustic design of a car. The air flow detached from the A-pillar and impacting the side windows are of particular interest as they are located close to the driver / passenger and provides a lower insulation index than the trimmed car body parts. HMC is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. The methodology proposed in this paper relies on two steps: the first step involves the computation of the exterior flow and turbulence induced non-linear acoustic field using the CAA(Computational aeroacoustics) solver CAA++. The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibro-acoustic solver Actran. The internal air cavity including trim component are included in the simulation. In order to validate the numerical process, an experimental set-up has been created based on a generic car shape. The car body includes the windshield and two side windows. The body is made of aluminum and trimmed with porous layers. First, this paper describes the method including the CAA and the vibro-acoustic models, from the boundary conditions to the different components involved, like the windows, the trims and the car cavity is detailed. In a second step, the experimental set-up is described. In the last part, the vibration of the windshield and windows, the total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements. The influence of the flow yaw angle (different wind orientation) is also assessed.

• 한국결정성장학회지
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• 제10권3호
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• pp.199-204
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• 2000

본 연구에서는 청색 발광다이오드, 광전모듈레이터, 태양전지의 창문층 등의 광범위한 응용분야를 갖는 ZnS를 용액 성장법에 의해 nanometer 사이즈의 입자로 구성된 박막의 형태로 슬라이드 유리기판에 성장하고 구조적, 광학적 특성을 분석하고, 이 결과를 토대로 ZnS박막의 양자사이즈효과에 대해 연구하였다. 성장조건에 관련된 인자는 precursor 용액의 농도, 성장온도, 암모니아 용액의 농도, 성장시간 등이었다. X-선 회절분석 결과, 본 연구에서 용액성장법으로 성장한 ZnS박막은 cubic 구조($\beta$-ZnS)를 가졌다. 성장온도가 $75^{\circ}C$일 때 막의 표면상태가 가장 양호했으며 입자사이즈의 균일도도 가장 우수했다 광에너지 변화에 따른 광투과도 측정 결과, 본 연구의 ZnS 시료는 성장조건을 조절함에 따라 에너지밴드갭이 3.69 eV~3.91 eV까지 조절 할 수 있었고, 이는 벌크 ZnS의 에너지밴드갭인 3.65 eV보다 훨씬 높은 수치로서 양자사이즈효과에 의한 blue-shift 현상이 용액성장법으로 합성된 ZnS에서 큰 폭으로 나타남을 알 수 있었다. 그리고 photoluminescence(PL)측정 결과, ZnS 입자의 미세성으로 인한 입자 표면준위의 영향으로 PL 피크가 에너지밴드갭보다 훨씬 적은 에너지 영역에서 발생했다. 특히 PL피크의 위치가 입자사이즈와 막두께에 따라 shift했는데, 이는 용액성장법으로 성장한 ZnS의 경우 본 연구에서 최초로 보고되는 것이다.