• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.48-56
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• 1989

Contact-type linear image sensors for facsimile have been fabricated by means of rf glow discharge decomposition method of silane. The dependence of their electrical and optical properties on rf power, $SiH_4$ flow rate, ambient gas pressure, $H_2SiH_4$ ratio and substrate temperature are described. The a-Si:H monolayer demonstriated photosensitivity of 0.85 and $I_{ph}/I_d$ ratio of 100 unger 100 lux illumination. However, this monolayer has relatively high dark current due to carrier injection from both electrodes, resulting in low $I_{ph}/I_{dd}$ ratio. To suppress the dark current we have fabricated $SiO_2/i-a-Si:H/p-a-Si:H:B$ multilayer film with blocking structure. The photocurrent of this multilayer sensor with 6 V bias became saturated ar about 20nA under 10 lux illumination, while the dark current was less than 0.2 nA. Moreover, the spectral sensitivity of the multilayer film was enhanced for short wavelength visible region, compared with that of the a-Si:H monolayer. These results show that the fabricated photocon-ductive film can be used as the linear image sensor of the facsimile.

• Journal of the Korean Chemical Society
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• v.52 no.6
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• pp.614-621
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• 2008

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.485-488
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• 2013

A SiC-$CeO_2$ composite membrane was successfully fabricated using an ally-hydridopolycarbosilane (AHPCS) binder and treated by dip-coating at 60 times with a $CeO_2$ sol solution. The dip-coated SiC membrane was calcined at 773 K and then sintered at 1173 K under an air atmosphere. The coated membrane was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and a BET surface analysis. The difference in permeation performance between $H_2$ and CO gases was measured by varying the temperature. The permeation flux of $H_2$ on the SiC membrane with layered $CeO_2$ was obtained as $8.45{\times}10^{-6}\;mol/m^2sPa$ at room temperature. The CO permeation flux was $2.64{\times}10^{-6}\;mol/m^2sPa$ at room temperature. The reaction enthalpy (${\Delta}H^{\circ}$) for the hydrogen permeation process was calculated as -7.82 J/mol by Arrhenius plots.

• Journal of the Korean Ceramic Society
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• v.32 no.6
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• pp.685-696
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• 1995

The most important techniques in the synthesis of SiC/C function gradient material (FGM) are to control the SiC/C ratio and to obtain the moderate deposition rate. For these, various gas systems and flow rates were attempted and evaluated. It turned out that the CH4＋SiCl4＋H2 system was suitable for the deposition of SiC-rich layers, the C3H8＋SiCl4＋Ar system for the deposition of carbon-rich layers, and the C3H8＋SiCl4＋H2＋Ar system was good to deposit the layers between them.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.73-77
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• 2002

Characteristics of Cu/Si/Cu ohmic contacts to n-type 4H-SiC were investigated systematically. The ohmic contacts were formed by rf sputtering of multi layer Cu/Si/Cu sputtered sequentially. The annealings were peformed With 2-Step using RTP in vacuum ambient. The specific contact resistivity($\rho$c), sheet resistance(Rs), contact resistance(Rc), transfer length(L$_{T}$) were calculated from resistance(R$_{T}$) versus contact spacing(d) measurements obtained from TLM(transmission line method) structure. Best results were obtained for a sample annealed at vacuum as $\rho$c = 1.0x10$^{-6}$ $\Omega$$\textrm{cm}^2$, Rc = 2$\Omega$ and L$_{T}$ = 1${\mu}{\textrm}{m}$. The physical properties of contacts were examined using XRO and AES. The results showed that copper silicide was formed on SiC and Cu was migrated into SiC.o SiC.

• Journal of the Korean institute of surface engineering
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• v.34 no.2
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• pp.135-141
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• 2001

Arc-melted Ti-6Al-4V, Ti-4Fe and Ti-(1,2) Si alloys were oxidized at 700, 800, 900 and $1000^{\circ}C$ in air. The oxidation resistance of Ti-4Fe was comparable to that of Ti-6Al-4V, while the oxidation resistance of Ti-(1,2) Si was superior to that of Ti-6Al-4V. Ti-2Si displayed the best oxidation resistance among the four alloys, but failed after oxidation at $1000^{\circ}C$ for 17h. The oxide scale formed on Ti-6Al-4V, Ti-4Fe and Ti-(1,2)Si consisted of ($TiO_2$ and a small amount of $Al_2$$O_3$), ($TiO_2$ and a small amount of dissolved iron), and ($TiO_2$ plus a small concentration of amorphous $SiO_2$), respectively. The oxide grains of the surface scale of the four alloys were generally fine and round.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.254.2-254.2
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• 2014

The Transmission Fourier Transform Infrared spectroscopy (FTIR) of SiOx charge storage layer with the richest silicon content showed an assignment at peaks around 2000~2300 cm-1. It indicated that the existence of many silicon phases and defect sources in the matrix of the SiOx films. The total hysteresis width is the sum of the flat band voltage shift (${\Delta}VFB$) due to electron and hole charging. At the range voltage sweep of ${\pm}15V$, the ${\Delta}VFB$ values increase of 0.57 V, 1.71 V, and 13.56 V with 1/2, 2/1, and 6/1 samples, respectively. When we increase the gas ratio of SiH4/N2O, a lot of defects appeared in charge storage layer, more electrons and holes are charged and the memory window also increases. The best retention are obtained at sample with the ratio SiH4/N2O=6/1 with 82.31% (3.49V) after 103s and 70.75% after 10 years. The high charge storage in 6/1 device could arise from the large amount of silicon phases and defect sources in the storage material with SiOx material. Therefore, in the programming/erasing (P/E) process, the Si-rich SiOx charge-trapping layer with SiH4/N2O gas flow ratio=6/1 easily grasps electrons and holds them, and hence, increases the P/E speed and the memory window. This is very useful for a trapping layer, especially in the low-voltage operation of non-volatile memory devices.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.240.1-240.1
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• 2012

We performed simultaneous observations of SiO v=1, 2, $^{29}SiO$ v=0, J=1-0 and $H_2O$ $6_{16}-5_{23}$ maser lines toward 252 OH/IR stars using the Korean VLBI Network 21m telescopes. The observations were carried out from 2011 November to 2012 July for studying SiO and $H_2O$ maser properties associated with the evolutionary stages of OH/IR stars. Both $H_2O$ and SiO masers were detected from 49 sources, one-side maser of SiO and $H_2O$ was detected from 109 and 11 sources, respectively. Mutual relations between SiO and $H_2O$ maser properties are investigated based on statistical analyses. We also investigate these maser properties in the IRAS two-color diagram related with stellar evolutionary sequence.

• Journal of Electrochemical Science and Technology
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• v.2 no.3
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• pp.168-173
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• 2011

The availability, low toxicity, and high degree of technological development make silicon the most likely material to be used in solar cells, the cost of solar cells depends entirely on cost of high purity silicon production. The present work was conducted to electrodeposite of silicon from $K_2SiF_6$, an inexpensive raw material prepared from fluorosilicic acid ($H_2SiF_6$) produced in Iraqi Fertilizer plants, and using inexpensive graphite material as cathode electrode. The preparation of potassium fluorosilicate was performed at ($60^{\circ}C$) in a three necks flask provided with a stirrer, while the electro deposition was performed at $750^{\circ}C$ in a three-electrodes configuration with melt containing in graphite pot. High purity potassium fluorosilicate (99.25%) was obtained at temperature ($60^{\circ}C$), molar ratio-KCl/$H_2SiF_6$(1.4) and agitation (600 rpm). Spongy compact deposits were obtained for silicon with purity not less than (99.97%) at cathode potential (-0.8 V vs. Pt), $K_2SiF_6$ concentration (14% mole percent) with grain size (130 ${\mu}m$) and level of impurities (Cu, Fe and Ni) less than (0.02%).

• Solar Energy
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• v.6 no.1
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• pp.12-23
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• 1986

The PECVD $SiN_x:H$ films were made from the $SiH_4-N_2$ gas mixtures under such deposition conditions as 0.01 to 1.0 of $SiH_4/N_2$ volume ratio, 0.1 to $0.8W/cm^2$ of RF power, and 100 to $400^{\circ}C$ of substrate temperature. The deposition rate, refractive index, hydrogen concentration, N/Si composition, optical gap and electric conductivity were measured, and the thermal stability and the optimum deposition conditions were investigated for the application of these films to the solar cell materials.