• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.45-45
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• 2004

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.167-171
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• 2004

The electroless deposition of copper on the hydrogen-terminated Si(111) surface was investigated by means of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, scanning tunneling microscopy (STM), and energy-dispersive spectroscopy (EDS). The hydrogen-terminated Si(111) surface prepared was stable under air atmosphere for a day or more. It was found from ATR-FTIR that two bands centered at 2000 and 2260 $cm^{-1}$ appeared after the H-Si(111) surface was immersed in 40% $NH_4F$ solution containing 10 mM $Cu^{2+}$. On the other hand, STM image included the copper islands with a height of 5 nm and a diameter of 10-20 nm. The EDS data displayed the presence of copper, silicon and oxygen species. The results were rationalized in terms of the redox reaction of surface Si atoms and $Cu^{2+}$ ions in solutions, which are changed into $Si(OH)_x(F)_y$ containing $SiF_6^{2-}$ ions and neutral copper islands.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.330-335
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• 2020

Silicon surface nanostructures, which can be easily prepared by electrochemical etching, have attracted considerable attention because of its useful physical properties that facilitate application in diverse fields. In this work, electrochemical and electrochemical-scanning tunneling microscopic (EC-STM) techniques were employed to study the evolution of surface morphology during the electrochemical etching of Si(111)-H in a fluoride solution. The results exhibited that silicon oxide of the Si(111) surface was entirely stripped and then the surface became hydrogen terminated, atomically flat, and anisotropic in the fluoride solution during chemical etching. At the potential more negative than the flat band one, the surface had a tendency to be eroded very slowly, whereas the steps of the terrace were not only etched quickly but the triangular pits also deepened on anodic potentials. These results provided information on the conditions required for the preparation of porous nanostructures on the Si(111) surface, which may be applicable for sensor (or device) preparation (Nanotechnology and Functional Materials for Engineers, Elsevier 2017, pp. 67-91).

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.647-651
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• 2016

SiC films were prepared on glassy carbon substrates by laser chemical vapor deposition under a high pressure of $10^4Pa$ using a diode laser (wavelength = 808 nm) and a polysilaethylene precursor. (111)-oriented SiC films were formed at a deposition temperature ($T_{dep}$) range of 1150 - 1422 K. At $T_{dep}=1262K$, the SiC film with a high Lotgering factor of above 0.96 showed an exhibited pyramid-like surface morphology and flower-like grains. The highest deposition rate ($R_{dep}$) was $220{\mu}m\;h^{-1}$ at $T_{dep}=1262K$.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1514-1516
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• 1999

This paper covers our efforts to improve the low carrier mobility and light instability of hydrogenated amorphous silicon (a-Si:H) films with microcrystalline silicon $({\mu}c-Si)$ films. We successfully prepared ${\mu}c-Si$ films on $CaF_2$/glass substrate by decomposition of $SiH_4$ in RPCVD system. The $CaF_2$ films on glass served as a seed layer for ${\mu}c-Si$ film growth. The XRD analysis on $CaF_2$/glass illustrated a (111) preferred $CaF_2$ grains with the lattice mismatch less than 5 % of Si. We achieved ${\mu}c-Si$ films with a crystalline volume fraction of 61 %, (111) and (220) crystal orientations. grain size of $706\AA$, activation energy of 0.49 eV, and Photo/dark conductivity ratio of 124. By using a $CaF_2$/glass structure. we were able to achieve an improved ${\mu}c-Si$ films at a low substrate temperature of $300^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.96.2-96.2
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• 2010

The surface morphology and structural properties of polycrystalline silicon (poly-Si) films made in-situ aluminum induced crystallization at various substrate temperature (300~600) was investigated. Silicon films were deposited by hot-wire chemical vapor deposition (HWCVD), as the catalytic or pyrolytic decomposition of precursor gases SiH4 occurs only on the surface of the heated wire. Aluminum films were deposited by DC magnetron sputtering at room temperature. continuous poly-Si films were achieved at low temperature. from cross-section TEM analyses, It was confirmed that poly-Si above $450^{\circ}C$ was successfully grown on and poly-Si films had (111) preferred orientation. As substrate temperature increases, Si(111)/Si(220) ratio was decreased. The electrical properties of poly-Si film were investigated by Hall effect measurement. Poly-Si film was p-type by Al and resistivity and hall effect mobility was affected by substrate temperature.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.477-483
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• 1998

$SiC_{4}$$C_{3}$$H_{ 8}$$H_{2}$와 $C_{3}$$H_{8}$ $H_{2}$, $CH_{3}$$SiCI_{3}$$CH_{4}$$H_{2}$계를 사용하여 흑연기판 위에 SiC와 SiC/C FGM을 CVD법에 의해 코팅하였다. $SiCI_{4}$$C_{3}$$H_{8}$ $H_{2}$ 계에서 SiC 증착 시 바람직한 수소의 비는 10-30사이였고 결정 배향성은 입력가스의 탄소비에 따라 여러번의 대 반전이 일어났다. 성장조건을 {111} 배향성을 갖도록 조절하는 것이 FGM층간 접착상태를 증진시킬 수 있는 방법으로 판단되었다. $CH_{3}$$SiCI_{3}$C$_{3}$$H_{8}$ $H_{2}$ 계에서는 SiC와 C의 비율을 조절하기가 $SiCI_{4}$$C_{3}$$H_{8} $H_{2}$계를 사용했을 때 보다 용이하였고, FGM 단면 관찰에서 층간의 뚜렷한 경계를 발견할 수 없을 정도로 우수한 층간 접착상태를 보였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.2
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• pp.56-59
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• 2001

Thin films of hydrogenated amorphous silicon (a-Si : H) of different compositions were deposited on Si(100) wafer and glass by RF plasma-enhanced chemical vapor deposition (PECVD). In the present work, we have investigated the effect of the If. power on the properties, such as optical band gap, transmittance and crystallinity, of crystalline silicon thin films. Raman data show that the material consists of an amorphous and crystalline phase for the co-presence of two peaks centered at 480 and 520cm$^{-1}$. X-ray spectra confirmed of crystallites with (111) orientation at 300w The transmittance of thin films was measured by UV-VIS spectrophotometer. In addition, Si-H chemical bondings were studied by Fourier Transform Infrared (FT-IR) spectroscopy.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.104-111
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• 2001

B-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films were prepared by plasma-enhanced chemical-vapor deposition in a gas mixture of $SiH_4, CH_4,\;and\; B_2H_6$. Physical and chemical properties of a-SiC:H films grown with varing the ratio of $B_2H_6/(SiH_4+CH_4)$ were characterized with various analysis methods including scanning electron microscopy (SEM), X-ray diffractometry (XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, secondary ion mass spectroscopy (SIMS), UV absorption CH_4spectroscopy and electrical conductivity measurements. With the B-doping concentration, the doping efficiency and the micro-crystallinity were decreased and the film became amorphous when $B_2H_6/(SiH_4{plus}CH_4)$ was over $5{\times}10^{-3}$. The addition of $B_2H_6$ gas during deposition decreased the H content in the film by lowering the quantity of Si-C-H bonds. Consequently, the optical band gap and the activation energy of a-SiC:H films were decreased with increasing the B-doping level.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.1
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• pp.49-54
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• 1998

The effect of deposition paratmeters on the solid-phase crystallization of amorphous silicon films deposited by plasma-enhanced chemical vapor deposition has been investigated by x-ray diffraction. The amorphous silicon films were prepared on Si(100) wafers using SiH4 gas with and without H2 dilution at the substrate temperatures between 12$^{\circ}C$ and 38$0^{\circ}C$. The R. F. powers and the deposition pressures were also varied. After crystallizing at $600^{\circ}C$ for 24h, the films exhibited (111), (220), and (311) x-ray diffraction peaks. The (111) peak intensity increased as the substrate temperature decreased, and the H dilution suppressed the crystallization. Increasing R.F. powers within the limits of etching level and increasing deposition pressures also have enhanced the peak intensity. The peak intensity was closely related to the deposition rate, which may be an indirect indicator of structural disorder in amorphous silicon films. Our results are consistent with the fact that an increase of the structural disorder I amorphous silicon films enhances the grain size in the crystallized films.