• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.387-390
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• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS(micro electro mechanical system) fields because of its application possibility in harsh environments. This paper presents pre-bonding techniques with variation of HF pre-treatment conditions for 2 inch SiC wafer direct bonding using PECVD(plasma enhanced chemical vapor deposition) oxide. The PECVD oxide was characterized by XPS(X-ray photoelectron spectrometer) and AFM(atomic force microscopy). The characteristics of the bonded sample were measured under different bonding conditions of HF concentration and an applied pressure. The bonding strength was evaluated by the tensile strength method. The bonded interface was analyzed by using IR camera and SEM(scanning electron microscope). Components existed in the interlayer were analyzed by using FT-IR(fourier transform infrared spectroscopy). The bonding strength was varied with HF pre-treatment conditions before the pre-bonding in the range of $5.3 kgf/cm^2$ to $15.5 kgf/cm^2$

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.298-299
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• 2011

최근 입력소자로 활용되는 터치스크린은 키보드나 마우스와 같은 입력장치를 사용하지 않고, 스크린에 손가락, 펜 등을 접촉하여 입력하는 방식이다. 터치패널의 구현방식에 따라 저항막(Resistive) 방식, 정전용량(Capacitive) 방식, SAW (Surface Accoustic Wave; 초음파) 방식, IR (Infrared; 적외선) 방식등으로 구분된다. 특히 최근 관심을 받고 있는 IR 방식은 적외선이 사람의 눈에는 보이지 않으나, 직진성을 가지고 있어 장애물이 있으면 차단되는 특성을 이용한 방식이다. IR방식의 터치패널은 발광(Light emitting)소자와 수광(Light detecting)소자가 마주하도록 배치되어 터치에 의해 차단된 좌표를 인식하게 되며, ITO 필름 등이 필요 없어 Glass 1장으로도 구현이 가능하며 투과율이 우수하다. 이러한 IR 방식의 터치패널을 제작하기 위하여 사용된 IR 광검출기는 광학적 band-gap이 작은 박막물질을 필요로 한다. 본 연구에서는 IR 광검출을 위한 물질로 SiGe를 co-sputtering 기법을 이용하여 성장시켰다. 일반적으로 SiGe 박막을 성장시키기 위하여 저압화학기상증착법(low pressure chemical vapor deposition, LPCVD)이나 고진공 LPCVD를 사용하지만 본 연구에서는 CVD에 비하여 무독성이면서 환경친화적이고 초기투자비용이 낮은 증착장비인 sputtering을 이용하였다. 본 연구에서 성장된 SiGe 박막은 400$^{\circ}C$에서 rf plasma가 인가된 Ge과 dc plasma가 인가된 Si의 power를 조절하여 결정화도가 70% (Fig. 1)이고 결정성장방향이 (111)과 (220)방향으로 성장하는 SiGe 박막을 얻을 수 있었다. 본 논문에서는 co-sputtering 성장조건에 따라 성장된 SiGe의 박막 특성을 논의할 것이다.

• The Korean Journal of Ceramics
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• v.3 no.1
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• pp.1-4
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• 1997

Diamond film (24$\mu\textrm{m}$) were prepared by Microwave Plasma Chemical Vapor Deposition method from a reactive CO/H$_2$ mixtures. Micro-Raman spectroscopy and micro-cathodoluminescence study were carried out along the crosssection and correlated to SEM observation. CL image of cross-section was also investigated. Peak position, FWHM of Raman spectrum were determined using Lorentzing fit. The stress in this sample is 0.4~0.7 GPa compressive stress, and along the distance the compressive stress reduced. The Raman peak broadening is dominated by phonon life time reduction at grain boundaries and defect sites. Defects and impurities were mainly present inside the film, not at Silicon/Diamond interface.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.1-4
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• 2000

Thin films of hydrogenated amorphous silicon carbide compounds ($a-Si_{x}C_{1-x}:H$) of different compositions were deposited on Si substrate by RF plasma-enhanced chemical vapor deposition (PECVD). Experiments were carried out using silane (SiH$_4$) and methane ($CH_4$) as the gas precursors at 1 Torr and at a low substrate temperature ($250^{\circ}C$). The gas flow rate was changed with the other parameters (pressure, temperature, RF power) fixed. The substrate was Si(100) wafer and all of the films obtained were amorphous. The bonding structure of $a-Si_{x}C_{1-x}:H$films deposited was investigated by X-ray photoelectron spectroscopy (XPS) for the film compositions. In addition, the surface morphology of films was investigated by atomic force microscopy (AFM).

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.38-39
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• 2006

We present experimental results that regard the effects of catalyst preparation on the structural and field-emissive properties of CNTs. The CNTs used in this research have been synthesized using the inductively coupled plasma-chemical vapor deposition (ICP-CVD) method. Catalyst materials (such as Ni, Co, and Invar 426) are varied and deposited on buffer films by RF magnetron sputtering. Prior to growth of CNTs, $NH_3$ plasma etching has also been performed with varying plasma etching time and power. For all the CNTs grown, nanostructures and morphologies are analyzed using Raman spectroscopy and FESEM, in terms of buffer films, catalyst materials, and pre-treatment conditions. Furthermore, the field electron-emission of CNTs are measured and characterized in terms of the catalyst preparation environments. The CNTs grown on Nicatalyst layer would be more effectual for enhancing the growth rate and achieving the vertical-alignment of CNTs rather than other buffer materials from results of SEM study. The crystalline graphitic structure of CNTs is improved as the catalyst dot reaches a critical size. Also, the field-emission result shows that the CNTs using Ni catalyst would be more favorable for improving electron-emission capabilities of CNTs compared with other samples.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.376-379
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• 2013

Multi-walled carbon nanotubes (MWCNTs) were synthesized using catalytic chemical vapor deposition (CVD) method. Oxygen plasma treatment was applied to modify surface state of the CNTs synthesized for improvement of field emission performance. Surface state of the plasma treated CNTs was studied by X-ray photoelectron spectroscopy (XPS). The surface states of the CNTs were changed as a function of plasma treatment time. The oxygen related carbon shift was moved toward higher binding energy with the plasma treatment time. This result implies that the oxygen plasma treatment changes the surface state effectively. While any shift in carbon 1s peak was not detected for the as grown CNTs, oxygen related carbon shift was detected for the plasma treated CNTs. Carbon shift implies that closed CNT tips were opened by the oxygen plasma and reacted with oxygen species. Since the field emission occurs at pentagons or dangling bonds of the CNT tips, the increase of carbon-oxygen bonds plays an important role in field emission behavior by increasing the number of electron emission sites resulting in improvement of the field emission performance.

• Electrical & Electronic Materials
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• v.4 no.4
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• pp.344-353
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• 1991

무정형 SiC 박막을 수평형 CVD반응기로부터 SiH$_{4}$ 및 H$_{2}$를 반응기체로 하여 실리콘 웨이퍼위에 증착시켜 제조하였다. 박막 성장 속도는 상압에서 650.deg.C와 850.deg.C범위에서 측정되었다. 반응기체의 유량은 1000sccm으로 고정하였으며 SiH$_{4}$와 CH$_{4}$의 유량을 변화시켰다. 증착 반응속도식으로 표면 반응이 율속단계인 Eley-Rideal 모델과 SiH$_{4}$와 CH$_{4}$의 종도에 m차로 비례하는 두가지 속도식을 가정하였다. 증착시간에 따른 SiC 박막두께의 측정으로부터 얻은 증착 반응 속도로부터 회귀 분석법에 의하여 두가지 반응속도식의 반응속도 상수를 구하였다. 얻어진 반응속도식에 의해서 계산된 값과 실험치를 비교한 결과 0.15차의 반응속도식이 Eley-Rideal반응기구보다 약산 더 잘 맞음을 알 수 있으나 두 모델 다 약간씩 실험결과와 차이가 나고 있다. 이것은 본 실험의 증착 조건의 율속단계가 확산 단계와 표면 반응 단계의 전이영역 즉 본 실험의 증착조건에서 확산속도와 표면 반응속도가 비슷하기 때문으로 생각된다. 또한 Eley-Rideal 반응기구에서 부터 얻어진 SiH$_{4}$ 및 CH$_{4}$의 흡착평형상수 $K_{s}$ 와 $K_{c}$ 값을 비교하면 1000K이하에서는 $K_{s}$ 가 $K_{c}$ 보다 큰 값을 가지는데 이것은 Gibbs 자유에너지 최소화 방법에서 구한 결과와 일치하였다.

• Electrical & Electronic Materials
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• v.7 no.4
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• pp.331-340
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• 1994

Polysilicon on insulator has been recrystallized by zone melting recrystallization method with graphite strip heaters. Experiments are performed with non-seed SOI structures. When the capping layer thickness of Si$\_$3/N$\_$4//SiO$\_$2/ is 2.0.mu.m, grain boundaries are about 120.mu.m spacing and protrusions reduced. After the seed SOI films are annealed at 1100.deg. C in NH$\_$3/ ambient for 3 hours, the recrystallized silicon surface has convex shape. After ZMR process, the tensile stress is 2.49*10$\^$9/dyn/cm$\^$2/ and 3.74*10$\^$9/dyn/cm$\^$2/ in the seed edge and seed center regions. The phenomenon of convex shape and tensile stress difference are completely eliminated by using the PSG/SiO$\_$2/ capping layer. The characterization of SOI films are showed that the SOI films are improved in wetting properties. N channel SOI MOSFET has been fabricated to investigate the electrical characteristics of the recrystallized SOI films. In the 0.7.mu.m thickness SOI MOSFET, kink effects due to the floating substrate occur and the electron mobility was calculated from the measured g$\_$m/ characteristics, which is about 589cm$\^$2//V.s. The recrystallized SOI films are shown to be a good single crystal silicon.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.700-704
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• 2003

This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 ％ and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.36-37
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• 2006

Both negative and positive substrate bias effects on the structural properties and field-emission characteristics are investigated. carbon nanotubes (CNTs) are grown on Ni catalysts employing an inductively-coupled plasma chemical vapor deposition (ICP-CVD) method. Characterization using various techniques, such as field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Auger spectroscopy (AES), and Raman spectroscopy, shows that the physical dimension as well as the crystal quality of CNTs grown can be changed and controlled by the application of substrate bias during CNT growth. It is for the first time observed that the prevailing growth mechanism of CNTs, which is either due to tip-driven growth or based-on-catalyst growth, may be influenced by substrate biasing. It is also seen that negative biasing would be more effectively role in the vertical-alignment of CNTs compared to positive biasing. However, the CNTs grown under the positively bias condition display much better electron emission capabilities than those grown under negative bias or without bias. The reasons for all the measured data regarding the structural properties of CNTs are discussed to confirm the correlation with the observed field-emissive properties.