• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 춘계학술발표강연 및 눈문개요집
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• pp.150-150
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• 1999

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.296-300
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• 2002

Thin films of Hydrogenated amorphous carbon(a-C:H) are generally exhibited by high electrical resistivities from 10$^2$ to 10$\^$16/ Ω$.$cm, resulting in an interesting material for high power, high temperature MIS devices applications. The hydrogenated amorphous carbon(a-C:H) films were deposited on silicon and glass using an rf plasma enhanced CVD method. The resultant film properties were evaluated in the respect of material based on r.f. power variation. The hydrogenated amorphous carbon(a-C:H) films of thickness ranging from 30 to 50 m were deposited at the pressure of 1 ton with the mixture of methane and hydrogen. We have used rf-IR( courier transform IR) and AFM(Atomic force microscopy) for determining physical properties and current-voltage(I-V) measurement for electrical Properties.

• Transactions on Electrical and Electronic Materials
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• 제10권3호
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• pp.75-79
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• 2009

An intrinsic silicon thin film passivation layer is deposited by the microwave remote-plasma enhanced chemical vapor deposition at temperature of $175^{\circ}C$ and various gas ratios for solar cell applications. The good quality amorphous silicon films were formed at silane $(SiH_4)$ gas flow rates above 15 seem. The highest effective carrier lifetime was obtained at the $SiH_4$, flow rate of 20 seem and the value was about 3 times higher compared with the bulk lifetime of 5.6 ${\mu}s$ at a fixed injection level of ${\Delta}n\;=\;5{\times}10^{14}\;cm^{-3}$. An annealing treatment was performed and the carrier life times were increased approximately 5 times compared with the bulk lifetime. The optimal annealing temperature and time were obtained at 250 $^{\circ}C$ and 60 sec respectively. This indicates that the combination of the deposition of an amorphous thin film at a low temperature and the annealing treatment contributes to the excellent surface and bulk passivation.

• 한국진공학회지
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• 제4권S2호
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• pp.64-68
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• 1995

Silicon films were deposited at $430^{\circ}C$ by remote plasma chemical vapor deposition(RPECVD) with a gas mixture of $Si_2H_6/SiF_4/H_2$. The silicon films deposited without and with $SiF_4$ were characterized using atomic force microscopy(AFM), transmission electron microscopy(TEM) and X-ray diffraction(XRD). Both silicon films have the same rugged surface morphology, but, the silicon film deposited with $SiF_4$ exhibits more rugged. The silicon film deposited without $SiF_4$ is amorphous, whereas the silicon film deposited with $SiF_4$ is polycrystalline with very small needle-like grains which are perpendicular to the substrate and uniformly distributed in the thickness of the film. The silicon film deposited with $SiF_4$ was found to have a preferred orientation along the growth direction with the<110> of the film parallel to the <111> of the substrate. The effect of $SiF_4$ during RPECVD was discussed.

• 한국표면공학회지
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• 제43권1호
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• pp.7-11
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• 2010

Solid phase crystallization (SPC) is a simple method in producing a polycrystalline phase by annealing amorphous silicon (a-Si) in a furnace environment. Main motivation of the crystallization technique is to fabricate low temperature polycrystalline silicon thin film transistors (LTPS-TFTs) on a thermally susceptible glass substrate. Studies on SPC have been naturally focused to the low temperature regime. Recently, fabrication of polycrystalline silicon (poly-Si) TFT circuits from a high temperature polycrystalline silicon process on steel foil substrates was reported. Solid phase crystallization of a-Si films proceeds by nucleation and growth. After nucleation polycrystalline phase is propagated via twin mediated growth mechanism. Elliptically shaped grains, therefore, contain intra-granular defects such as micro-twins. Both the intra-granular and the inter-granular defects reflect the crystallinity of SPC poly-Si. Crystallinity and SPC kinetics of high temperatures were compared to those of low temperatures using Raman analysis newly proposed in this study.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권4호
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• pp.185-189
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• 2004

The temporal variation of a secondary electron emission coefficient (${\gamma}$ coefficient) of hydrogenated amorphous silicon (a-Si:H) was investigated in a dc silane plasma. Estimated ${\gamma}$ coefficients have a value of 2.73 ${\times}$ 10$^{-2}$ on the pure aluminum electrode and 1.5 ${\times}$ 10$^{-3}$ after 2 hours deposition of -Si:H thin films on a cathode. It showed an abrupt decrease for about 30 minutes before saturation. The variation of the ${\gamma}$ coefficient was estimated as a function of the thin film thickness, and the film thickness was about 80 nm after 30 minutes deposition time. These results are compared with the results of a computer simulation for ion penetration into a cathode.

• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2909-2912
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• 2010

Hydrogenated microcrystalline silicon (${\mu}c$-Si:H) thin film for solar cells is prepared by plasma-enhanced chemical vapor deposition and physical properties of the ${\mu}c$-Si:H p-layer has been investigated. With respect to stable efficiency, this film is expected to surpass the performance of conventional amorphous silicon based solar cells and very soon be a close competitor to other thin film photovoltaic materials. Silicon in various structural forms has a direct effect on the efficiency of solar cell devices with different electron mobility and photon conversion. A Raman microscope is adopted to study the degree of crystallinity of Si film by analyzing the integrated intensity peaks at 480, 510 and $520\;cm^{-1}$, which corresponds to the amorphous phase (a-Si:H), microcrystalline (${\mu}c$-Si:H) and large crystals (c-Si), respectively. The crystal volume fraction is calculated from the ratio of the crystalline and the amorphous phase. The results are compared with high-resolution transmission electron microscopy (HR-TEM) for the determination of crystallinity factor. Optical properties such as refractive index, extinction coefficient, and band gap are studied with reflectance spectra.

• 한국세라믹학회지
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• 제42권5호
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• pp.359-365
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• 2005

Silicon nitride coating films with various ratios of nitrogen to silicon contents were prepared and characterized. The film was coated on silicon substrate by sputtering method with changing nitrogen gas flow rate in a chamber. The nitrogen to silicon ratio was found to have values in a range from 0 to 1.4. Coated film was characterized with scanning electron microscopy, transmission electron microscopy, electron probe microanalysis, nanoindentation scanning probe microscopy, x-ray photon spectrometry, and Raman spectrometry. Silicon nitride phase in all samples showed amorphous nature regardless of N/Si ratio. When N/Si ratio was 1.25, hardness and elastic modulus of silicon nitride film showed maximum with 22 GPa and 210 GPa, respectively. Those values decreased, when N/Si ratio was higher than 1.25. Raman spectrum showed that no silicon phase exist in the film. XPS result showed that the silicon-nitrogen bond was dominant way for atomic bonding in the film. The structure and property was explained with Random Bonding Model(RBM) which was consistent with the microstructure and chemistry analysis for the coating films.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.128.1-128.1
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• 2011

In amorphous silicon and crystalline silicon(a-Si:H/c-Si) heterojuction solar cells, intrinsic hydrogenated amorphous silicon(a-Si:H) films play an important role to passivate the crystalline silicon wafer surfaces. We have studied the correlation between the surface passivation quality and nature of the Si-H bonding at the a-Si:H/c-Si interface. The samples were obtained by VHF-CVD under different deposition conditions. The passivation quality and analysis of all structures studied was performed by means of quasi steady state photoconductance(QSSPC) methods and fourier transform infrared spectrometer(FTIR) measurements respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1019-1021
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• 1995

Light induced degradation of hydrogenated amorphous silicon(a-Si:H) are related to the number of weak dangling bonds which are thought to be responsible for the Staebler-Wronski effects, and caused the many photoelectric problems in applications of thin film transistors and solar cell, etc. In this paper, we deposited fluorinated amorphous silicon films(a-Si:H;F) with $SiH_4$ and $SiF_4$ gas mixture and investigated the effects of fluorine atoms on the evoluations of the crystallinity and improvements of light instability. We have found that micro-crystallinity produced in a-SI:H;F films and marked maximum value of 22% at the flow rate of $SiH_4:SiF_4$=2:10 sccm by UV spectrophotometer measurement, while n-Si:H film deposited with only $SiH_4$ gas showed no crystallinity. Light-induced degradation property of a-Si:H;F films is also improved which is mainly due to the etching effects of fluorine atoms on the weak Si-Si bonds and unstable hydrogen bonds. It is considered that involving fluorine atoms in a-Si:H films may contribute to the suppression of light-induced degradation and evolution of micro-crystallinity.