• Journal of the Korean Vacuum Society
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• v.5 no.3
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• pp.239-244
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• 1996

We firstly report that formation of $SiO_2$ layer on Si surface can be effectively prevented by flowing the $Si_2H_6$ gas during the heating-up procedure for amorphous Si depositions. In this way, amorphously deposited Si layer onto crystalline Si substrates can be grown epitaxially during the post-deposition heat treatments. The suppression of surface $SiO_2$ can be explained in terms of adsorption of SiHx adspecies, instead of oxygen from residual gases in the reactors, to Si surfaces after desorption of hydrogen from H-passivated Si surfaces. Employing $Si_2H_6$ flowing and soild phase epitaxial growth, high-quality epitaxial Si layer can be obtained at low temperatures below $600^{\circ}C$ without conventional high temperature cleaning procedures.

• Textile Coloration and Finishing
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• v.11 no.5
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• pp.44-54
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• 1999

Poly(ethylene 2,6-naphthalate), PEN, is a relatively well-known polymer used for engineering purposes. Naphthalene ring provides rigidity to the polymer backbone, thus, it elevated the glass transition temperature and enhanced mechanical properties. The structure and properties of PEN affect a processing conditions severely, and the high-thermal stability have been had a poor thermal processibility. Hence, the basic mechanism of solvent drawing, is very much the same as that of thermal drawing from glassy state since both involve the inducement of segmental mobility. The former achieves the goal by use of chemical energy, and the latter does so by use of thermal energy. Generally, the sorption of the solvent by the polymer has a plasticizing effect, and leads to a lowering of the glass transition temperature, $T_g$. In this paper, the dynamic viscoelasticity behavior in liquid-drawing process of an unoriented amorphous PEN films were investigated using Rheovibron. The results are as follows ： (1) For the drawing in silicone oil, the drawing below $T_g$. had $\alpha{2}$-dispersion due to an inhomogeneous taut structure. (2) For the drawing in water, the inhomogeneous taut structure reduced by the effect of plasticization even below $T_g$. (3) For the drawing in butanol, the only aliphatic segment in PEN have some molecular mobility but the mobility of the aromatic segment having naphthalene ring is nearly impossible. (4) For the drawing in dioxane/water mixing solvent, the solvent effect is complementary each other and accordingly the entire molecular conformation have stable state. (5) For the drawing in dioxane/butanol mixing solvent, the inhomogeneity of the taut structure and the aromatic segment increase with increasing the temperature and this tendencies correspond with that of the draw ratio.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.112-116
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• 2005

We investigated the surface modification method for the preparation of organic-inorganic hybrid composite thin film. Gelatin obtained from the decomposition of collagen was allowed to adsorb in a polystyrene tissue culture dish for 2 h to from layers of gelatin. Supersaturated ionic solution of calcium and phosphorus was injected on the gelatin adsorbed layer to form calcium phosphate thin film. During the initial period of incubation, nucleates were formed. With increase of the incubation time, CaP (calcium phosphate) thin film grew on the surface of the culture dish. The gelatin/CaP thin film displayed the highly porous three-dimensional surface structure. Attenuated, total reflectance Fourier transform, infra-red spectroscopy (ATR-FTIR) was used to analyze the chemical properties of CaP film. The analysis demonstrated that the CaP film formed at initial period of treatment appeared to be amorphous. With increase of incubation time, the crystallinity of the film was slightly increased, but the presence of the peaks for the low crystalline CaP confirmed that the CaP thin film prepared in this study was poorly crystallized.

• Polymer(Korea)
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• v.25 no.6
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• pp.803-810
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• 2001

A nonlinear optical hyperbranched polyester (PE-Azo/Hyper) was synthesized from 4-[N,N-bis(hydroxyethyl)amino-4'-formyl] azobenzene and cyanoacetic acid by a Knoevenagel polycondensation using 4-(dimethylamino) pyridine as a base. The resulting polymer was soluble in polar aprotic solvents such as N,N-dimethylformamide and 1-methyl-2-pyrrolidinone and could be processed into optical quality films by spin coating. The molecular weight was determined to be $M_w$=61,800 ($M_W/M_n{=1.86}$) by gel permeation chromatography using polystyrene as a standard. No melting point was detected by differential scanning Calorimeter, indicating that this polymer presents an amorphous state. It shows a glass transition temperature of $121^{\circ}C$. The second-order nonlinear optical coefficient $d_{33}$ of the poled polymer determined by the second harmonic generation at 1064 nm was 25.4 pm/V.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.83-89
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• 1989

Ferroelectric $PbTiO_3$ thin film is deposited with rf sputtering at substrate temperature of $100-150^{\circ}C$. It is found that this has pyrochlore structure of amorphous type by X-ray diffractive analysis. Thermal annealing has excellent characteristics at $550^{\circ}C$ and laser annealing has best crystalline structure in case of scanning with 50 watts. Interface states in MFST and MFOST structure with a $PbTiO_3$ ferroelectric thin film gate have been investigated from analysis of C-V data. The interface states density has been drastically reduced by inserting an oxide layer between ferroelectric and semiconductor. The observed effect increase feasibility of employing ferroelectric thin films such as nonvolatile memory field effect transistor, IR optical FET, and Image Devices with a ferroelectric layer.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1171-1177
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• 1999

The changes on microstucture of recombinated gels with different ratio of amylose(A) and amylopectin(AP) which were isolated from nonwaxy rice starch were investigated by scanning electron microscope(SEM) and X-ray diffractometer. As the concentration of amylose was above 3%(1.08% of soluble amylose) in the amylose suspension, gel matrix became like a three-dimensional network. The microstructure of amylose gels showed a network including macroporous structure, but the higher the ratio of amylopectin content were, the firmer network were formed. In case of A/AP mixed gels(15%) with different amylose/amylopectin percent ratios ; 0/5, 5/10, 10/5, 15/0%, as the storage time of gels and the percent ratio of amylose content were increased, network was formed harder with thick films. While X-ray diffractograms of waxy rice starch which contained 100% amylopectin showed A type, those of purified amylose and amylopectin showed V type and amorphous patterns, respectively. Amylose(3%) gels added $2{\sim}3%$ amylopectin and A/AP mixed gels(15%) showed peak at $2{\theta}\;=\;17.0^{\circ}$which were shown B type crystallinity similar af retrograded starches. Also as the percent ratio of amylose content in mixed gels was increased, peak intensity wat increased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1747-1752
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• 2012

The SiOC film of carbon centered system was prepared using bistrimethylsilylmethane (BTMSM) and oxygen mixed precursor by the chemical vapor deposition. The dielectric constant is measured by MIS(metal/insulator/Si) structure, but it could decrease the reliability because the uniformity is not assured. To research the dielectric constant of SiOC film, the range of low polarization was researched in SiOC film using the optical analysis and hardness, and then calculated the dielectric constant of SiOC film with amorphous structure of high degree. After annealing, the dielectric constant of SiOC film was decreased owing to the lowering of polarization, and FTIR spectra of the main bond was shifted to higher wave number. The main bond of 950~1200 cm-1 was composed of the Si-C and Si-O bonds. The intensity increases in Si-O bond infers the bonding strength became stronger than that of deposited film. Annealed SiOC film showed 2.06 in dielectric constant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.998-1001
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• 2004

ZnO, $SnO_2$ 타겟 각각의 RF 파워를 50 W, 38 W로 고정시킨 후 combinatorial RF magnetron sputtering법을 사용하여 기판 위치에 따라서 조성 구배를 주어 여러 가지 조성의 Zn-Sn-O(ZTO) 박막을 제작하였다. 시편의 열처리에 따른 물성 변화를 분석하기 위해 Rapid Thermal Annealer(RTA)을 이용하여 450, $650{^\circ}C$의 온도 및 $10^{-2}$ Ton의 진공 분위기에서 각각 1 시간 동안 열처리하였다. XRD 분석 결과 상온에서 제작된 ZTO 박막은 Sn 18 at%의 조성을 갖는 시편을 제외하고 모두 비정질상으로 나타났다. $450^{\circ}C$에서 열처리 후 구조적인 변화는 보이지 않았으나, 캐리어 농도와 이동도는 증가하였으며 Sn 54 at%의 조성에서 최고 $25.4cm^2/Vsec$의 전자 이동도를 나타내었다. $26{\leq}Sn$ $at%{\leq}65$의 조성 범위를 갖는 박막은 가시광 영역에서 80 % 이상의 투과도를 가졌으며 $650^{\circ}C$에서 결정화가 되면서 투과도가 증가하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.185-190
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• 2015

In this study, we fabricated the indium gallium zinc oxide (IGZO), zinc oxide (ZnO), aluminum zinc oxide (AZO). oxide and silver are deposited by magnetron sputtering and thermal evaporator, respectively transparency and energy bandgap were changed by the thickness of silver layer. To fabricate metal oxide metal (OMO) structure, IGZO sputtered on a corning 1,737 glass substrate was used as bottom oxide material and then silver was evaporated on the IGZO layer, finally IGZO was sputtered on the silver layer we get the final OMO structure. The radio-frequency power of the target was fixed at 30 W. The chamber pressure was set to $6.0{\times}10^{-3}$ Torr, and the gas ratio of Ar was fixed at 25 sccm. The silver thickness are varied from 3 to 15 nm. The OMO thin films was analyzed using XRD. XRD shows broad peak which clearly indicates amorphous phase. ZnO, AZO, OMO show the peak [002] direction at $34^{\circ}$. This indicate that ZnO, AZO OMO structure show the crystalline peak. Average transmittance of visible region was over 75%, while that of infrared region was under 20%. Energy band gap of OMO layer was increased with increasing thickness of Ag layer. As a result total transmittance was decreased.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.41-47
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• 2010

The effects of thermal treatment on CNTs, which were coated with a-$CN_x$ thin film, were investigated and related to variations of chemical bonding and morphologies of CNTs and also properties of field emission induced by thermal treatment. CNTs were directly grown on nano-sized conical-type tungsten tips via the inductively coupled plasma-chemical vapor deposition (ICP-CVD) system, and a-$CN_x$ films were coated on the CNTs using an RF magnetron sputtering system. Thermal treatment on a-$CN_x$ coated CNT-emitters was performed using a rapid thermal annealing (RTA) system by varying temperature ($300-700^{\circ}C$). Morphologies and microstructures of a-$CN_x$/CNTs hetero-structured emitters were analyzed by FESEM and HRTEM. Chemical composition and atomic bonding structures were analyzed by EDX, Raman spectroscopy, and XPS. The field emission properties of the a-$CN_x$/CNTs hetero-structured emitters were measured using a high vacuum (below $10^{-7}$ Torr) field-emission measurement system. For characterization of emission stability, the fluctuation and degradation of the emission current were monitored in terms of operation time. The results were compared with a-$CN_x$ coated CNT-emitters that were not thermally heated as well as with the conventional non-coated CNT-emitters.