• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.359-364
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• 1996

$SrTiO_3$ thin films were deposited on Pt/Ti/$SiO_2$/Si substrates at low temperatures below $300^{\circ}C$ by r.f. magnetron sputtering. The materials and the electrical properties of the deposited films were investigated with controlling deposition parameters such as substrate temperature(T_s) and positive substrate d.c. bias voltage. Stoichiometric $SrTiO_3$ films were obtained at Ts of $300^{\circ}C$, but Sr content in the film was less than that of a target when Ts was lower than $300^{\circ}C$, resulting in poor electrical properties. By introducing a positive substrate d.c. bias during deposition, the crystallinity and the dielectric properties of the films were markedly improved. 400 nm thick $SrTiO_3$, films deposited at $300^{\circ}C$ with a positive substrate d.c. bias of 20V showed a columnar structure with <211> crystallographic direction and a dielectric constant of 98.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.569-574
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• 2001

The crystal structure, surface morphology and preferred orientation of the copper electrodeposit were investigated by the using sulfate bath with $SiO_2$suspensions and the cathode substrate Au sputtered. As by the addition of colloidal silica in copper electrolytic bath and Au pre-coating on substrate, the crystal particles of deposits was fined-down, made uniform and the account of particles were increased. Hardness of copper electrodeposits with colloidal silica increased about 15% in comparison with that of pure copper deposit film and (111), (200) and (311) plane of X-ray diffraction patterns were almost swept away, so preferred orientation of the copper deposits changed from (111) to (110) plane by codeposit $SiO_2$ and precoating the substrate.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.399-409
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• 2016

Gyeongsangbuk-do moved its provincial office in October, 2015 and has been building a new town with a goal to construct a truly self-sufficient city with the population of 100,000 people before 2027. However, a new town tends to be dualized in terms of its administrative districts, so it is raising a lot of problems regarding from city construction up to operation. In order to solve those problems, this author has selected Si Gun Gu integration that was chosen as a major task to do in 2012 among the basic plans to revise the local administration system announced by the promotional committee to reorganize administrative districts as the range of this research and analyzed how it is going on in Andong-si and Yecheon-gun where a provincial office new town is being constructed. The main contents of this study regard the theoretical model to reform the local administration system, basic plans to revise the local administration system, and necessity and directions for reorganizing administrative districts in Andong-si and Yecheon-gun. Based on that, this author suggests integration of administrative districts as a way for a provincial office new town to establish its identity and grow as a sustainable, new growth focus city in Gyeongsangbuk-do.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.222-225
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• 2009

The apartment housing in Korea has been rapidly constructed by adapting the most suitable construction methods as like wall structure, wet and united construction. But most of short-lived equipments usually filled in the structure which has longer life, and it causes not only to make difficult coping with the deterioration of equipments but also to let buildings remained deteriorate themselves. The buildings can be remodelled to slow down the terms of deterioration or reconstructed to give a new life of themselves, although the disposal of wastes or the lack of natural resources still be problems and unsolved that can occurred in pulling down and reconstructing the buildings. Furthermore, it is the time to need keeping with worldwide trends and movements as like sustainability or 'green growth' movements based on low carbon emissions. The researches for Long-Life Housing apartments which has durability and variation have been advanced up to now. Long-Life Housing apartments can separate their structures from equipments and interior or exterior materials of buildings. Therefore equipments or materials of buildings can be easily repaired and replaced with new ones, even if they are deteriorated themselves. Also, the construction process of Long-Life Housing apartments can be independent from the matter of proprietary rights, terms of durability, decision rights and so on. 'The law of Possession and Management of Collective Building' and the 'Regulation of Management of Collective Building' established by each local governments are already legislated for declaring the rights of using and ownership, responsibilities of each parts of apartment buildings. These laws and regulations classify the ownership of each parts of apartment buildings, and divide the ownership with public possession and exclusive possession. Therefore, this study will conduct comparative analysis between 'The law of Possession and Management of Collective Building' and 'the Regulation of Management of Collective Building' and find problems which can be occurred in future construction of Long-Life Housing apartments. It will be helpful to revise laws and regulations.

• Journal of IKEEE
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• v.10 no.2 s.19
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• pp.156-160
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• 2006

Capacitance versus voltage (C-V) curves of Ge-nanocrystal (NC)-embedded MOS capacitors with and without a single capping Al2O3 layer are characterized in this work. C-V curves of the Ge-NC-embedded MOS capacitor with the A12O3 layer are counterclockwise in the voltage sweeps, which indicates tile presence of charge storages in the Ge NCs by the tunnelling of charge carriers between the Si substrate and the Ge NCs. In the Ge-NC-embedded MOS capacitor without Al2O3 layer, clockwise hysteresis of the C-V curves and leftward shifts of the flat band voltages are observed for the embedded MOS capacitor without the Al2O3 layer. It is suggested that the characteristics of the C-V curves are due to the charge trapping at oxygen vacancies within a SiO2 layer. In addition, the illumination of the white light enhances the lower capacitance part of the C-V hysteresis. The origin for the enhancement is discussed in this paper.

• Imaging Science in Dentistry
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• v.38 no.2
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• pp.81-87
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• 2008

Purpose: To investigate the relationship between 3D bone architectural parameters and direction-related elastic moduli of cancellous bone of mandibular condyle. Materials and Methods: Two micro-pigs (Micro-$pig^R$, PWG Genetics Korea) were used. Each pig was about 12 months old and weighing around 44 kg. 31 cylindrical bone specimen were obtained from cancellous bone of condyles for 3D analysis and measured by micro-computed tomography. Six parameters were trabecular thickness (Tb. Th), bone specific surface (BS/BV), percent bone volume (BV/TV), structure model index (SMI), degree of anisotropy (DA) and 3-dimensional fractal dimension (3DFD). Elastic moduli of three orthogonal directions (superior-inferior (SI), medial-lateral (ML), andterior-posterior (AP) direction) were calculated through finite element analysis. Results: Elastic modulus of superior-inferior direction was higher than those of other directions. Elastic moduli of 3 orthogonal directions showed different correlation with 3D architectural parameters. Elastic moduli of SI and ML directions showed significant strong to moderate correlation with BV/TV, SMI and 3DFD. Conclusion: Elastic modulus of cancellous bone of pig mandibular condyle was highest in the SI direction and it was supposed that the change into plate-like structure of trabeculae was mainly affected by increase of trabeculae of SI and ML directions.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.816-819
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• 1995

(Ba$_{1-x}$ , Sr$_{x}$)TiO/$_3$thin films on Pt/Ti/SiO$_2$/Si substrates were prepared by LP MOCVD(Low Pressure Metal-Organic Chemical Vapor Deposition). The crystalinity of BST deposit had a (100) preferred orientation with increasing deposition temperature due to surface diffusion. BST films deposited at 90$0^{\circ}C$ showed a dielectric constant of 365 and a dissipation factor of 0.052 at a frequency of 100kHz. The chance of capacitance of the films with applied voltage was small, showing paraelectric properties. BST film deposited at 90$0^{\circ}C$ had a charge storage density of 60 fc/${\mu}{\textrm}{m}$$^2$at a field of 0.2MV/cm and the leakage current density of 20 nA/$\textrm{cm}^2$ at a field of 0.15 MV/cm.cm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.3
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• pp.273-277
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• 2005

We prepared $0.25\~l.5um$ poly silicon gate array test group with $SiO_2$ spacers in order to employ NiCo composite salicide process from 15nm Ni/15nm Co/poly structure. We investigate the residual metal shape evolution by varying the rapid thermal silicide anneal temperature from $700^{\circ}C\;to\;1100^{\circ}C$. We observed the residual metals agglomerated into maze type and line type on $SiO_2$ field and silicide gate, respectively as temperature increased. We propose that lower silicide temperature would be favorable in newly proposed NiCo salicide in order to lessen the agglomeration causing the leakage and scum formation.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.170-170
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• 2011

태양전지와 박막 트랜지스터를 위한 유망한 재료로서 수소화된 비정질 실리콘과 나노결정 실리콘 박막이 관심을 받아 왔다. 특히, 수소화된 나노결정 실리콘 박막은 비정질 대비 높은 방향성과 조밀한 구조 덕에 박막 태양전지나 TFT(Thin film transistor) 소자의 성능 향상에 기여할 수 있는 물질로 연구되고 있다. 이러한 박막들은 보통 $SiH_4$같은 Si을 포함한 가스에 다량의 $H_2$를 희석시켜 플라즈마 화학 증착법(PECVD, Plasma Enhanced Chemical Vapor Deposition)에 의해 성장된다. 이러한 CVD증착 방식을 이용하여 결정화된 박막을 얻기 위해서는 대개 높은 수소 희석비를 이용하는 것이 일반적이나, 이러한 공정 방식은 실리콘이 결합되어야 할 결합위치에 bonding energy가 더 높은 수소의 결합을 촉진하게 된다. 이러한 특성은 박막 태양전지에서 효율을 떨어뜨리는 주요 요소로 작용하고 있다.(1) 본 연구에서는 수소의 결합 확률을 낮춘 결정화된 박막을 성장시키기 위해 수소를 대신하여 헬륨을 희석가스로 사용하여 박막을 증착하고 그 특성을 분석해 보았다. 박막의 구조적 특성, 결정화도(Xc), 플라즈마 내 활성 라디칼(Active radical in plasma), Si-H결합 특성, 전도도(Conductivity)와 같은 박막 특성을 알아보기 위해 주사전자현미경(SEM, Scanning Electron Microscopy), 라만 분광기(Raman spectroscopy), 광 방출 분광기(OES, Optical Emission Spectrocopy), 적외선 분광기(FT-IR, Fourier Transform-Infrared Spectroscopy), Keithley measurement kit이 사용되었다. 수소를 대신하여 헬륨을 사용함으로써 동일 결정화도 대비 10%이상 낮은 microstructure factor 값을 얻을 수 있었으며 인가되는 RF 전력을 140W까지 증가시켰을 때 약 80%의 결정화도를 관찰할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.348-348
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• 2012

CTF 메모리 소자는 높은 집적도와 낮은 구동전압과 CMOS 공정을 그대로 사용할 수 있고 비례 축소가 용이하다는 장점을 가지기 때문에 많은 연구가 진행되고 있다. CTF 메모리의 게이트 크기가 30 nm 이하로 작아짐에 따라 메모리 셀 간의 간섭이 매우 크게 증가하는 문제점이 있다. 이 문제점을 해결하기 위해 낸드 플래쉬 메모리 소자에서 셀 간 간섭 현상에 대한 많은 연구가 진행되고 있다. 본 연구에서는 $TaN-Al_2O_3-SiN-SiO_2-Si$ (TANOS) 플래쉬 메모리 소자에서 recess field의 모양에 따른 전기적 특성을 시뮬레이션 하였다. Recess field는 각 전하 트랩 층의 word 라인 방향에 존재하며 셀 간 간섭 효과를 줄이고 메모리 소자의 coupling ratio를 증가시키는 효과를 가지고 있다. TANOS 메모리 소자의 게이트 크기를 25 nm 에서 40 nm 로 변화하면서 round 타입의 recess field와 angular 타입의 recess field 에 대한 전기적 특성을 3차원 시뮬레이션 툴인 Sentaurus를 이용하여 시뮬레이션 하였다. Recess field를 가지지 않은 TANOS 메모리의 셀 간 간섭 효과는 게이트의 크기가 40 nm에서 25 nm 줄어들 때 많이 증가한다. 시뮬레이션된 결과에서 recess field의 모양에 상관없이 깊이가 늘어남에 따라 셀 간 간섭효과가 감소하였다. Recess field 의 깊이가 커짐에 따라 surrounding area가 늘어나 coupling ratio 가 증가하였다. Recess field 의 깊이가 증가함에 따라 프로그램 동작 시 트랩 층에 트랩 되는 전하의 수가 증가하고 recess field가 Si 기판의 표면에 가까이 위치할수록 coupling ratio, 드레인 전류 및 동작속도가 증가하였다. Recess field의 모양에 달리 하였을 때는 round 타입의 recess field를 가진 플래쉬 메모리 디바이스가 angular 타입의 recess field를 가진 소자와 비교하여 채널 표면의 잉여 전계가 감소하여 subthreshold leakage current 감소하였다. 본 연구의 시뮬레이션 결과는 수십 나노 스케일의 CTF 낸드 플래쉬 메모리 전기적 특성을 이해하는데 도움을 줄 것이다.