• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.682-685
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• 2003

In this paper, we propose the method to measure the Young's modulus of carbon nano tube which was manufactured by chemical vapor deposition. We also made the tungsten tip by electrochemical etching process and the carbon nano tube which was detangled through ultra-sonication with isopropyl alcohol was attached to the tungsten tip. This tip which was composed of tungsten tip and carbon nano tube can be used in Young's modulus measurement by applying DC voltage with counter electrode. The attachment process and measurement of the deflection of carbon nano tube was done under optical microscope.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.883-886
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• 1999

We deposited tungsten gate electrode on gate SiO$_2$by thermal LPCVD with WF$_{6}$, SiH$_4$ and H$_2$. The resistivity was ~10$\mu$Ωcm and exhibited good adhesion ability on oxide when the temperature was higher than 40$0^{\circ}C$. We find that, however, both the low-field current and the charge-trapping characteristics were inferior to the control devices. The oxide degradation by fluorine during the tungsten deposition must be minimized to use the tungsten as alternative gate electrode.e.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.157-157
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• 1999

Electrochromic tungsten oxide films were prepared by the electron beam deposition, and the dependence of the electrochemical stability and the optical properties on the titanium concentration, and on the annealing temperature, that was investigated. coloring and bleaching experiments were repeated by cyclic voltammetry in a propylene carbonate solution of LiClO4. Spectrometry was used to assess the stability of the transmittance in the degraded films. Tungsten oxide films with titanium contents of about 10~15 mol% were found to be most stable, undergoing the least degradation during the repeated for coloring and bleaching cycles. The reason for this small amount of degradation was the reduction of lithium ion trapping sites in the films, which results in an increased durability. Tungsten oxide films with titanium contents of about 20 mol% were annealed at 20$0^{\circ}C$ for 1 hour, and this results showed that durability of films were increased.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.19-26
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• 1992

The rate of tungsten nuclei formation from $WF_6-SiH_4$ on silicon dioxide surface was measured. The nucleation rate became faster at high deposition temperature, low carrier gas flow rate and high deposition pressure. Also the rate became faster at the downstream of the oxide surface compared to the oxide surface near the inlet. Shape and cross-sectional view of the tungsten nuclei were observed with SEM and their chemical compositions were also determined.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.624-628
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• 2000

As a power durable-electrode in SAW filter, Al-1%Cu/tungsten nitride multi-layer thin film was fabricated by magnetron sputtering process. Tungsten nitride films had the amorphous phase at the nitrogen ratio, R, ranging from 10~40%. The amorphization could be controlled by nitrogen ratio, R= $N_2$/($N_2$+Ar) as a sputtering process parameter. Residual stress in tungsten nitride abruptly decreased with the formation of amorphous phase. Al-1%Cu thin film was deposited on the amorphous tungsten nitride. After the multi-layed thin film was annealed for 4 hours at 453K, the resistivity decreased as $3.6{\mu}{\Omega}-cm$, which was due to grain growth reduced crystal defects.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.960-964
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• 2004

[ $Ba_2NaNb_5O_{15}$ ](BNN) thin films have been prepared by the ion beam sputter deposition (IBSD) method on Pt coated Si substrate at temperature as low as $600^{\circ}C$ XRD, SEM were used to investigate the crystallization and microstructure of the films. It was found that the films were crack-free and uniform in microstructure. The electric properties of thin films were carried out by observation of D-E hysteresis loop, dielectric constant and leakage current. It was found the deposition rate strongly influenced the phase formation of the films, where the phase of $BaNb_2O_6$ was always formed when the deposition rate was high. However, the single phase (tungsten bronze structure ) BNN thin film was obtained with the deposition rate as low as $22{\AA}/min$. The remanent polarization Pr and dielectric constant are about 1-2 ${\mu}C/cm^2$ and $100\sim200$, respectively. It was also founded the electric properties of thin films were influenced by the deposition rate. The Pr and dielectric constant of films increased with the decrease of deposition rate. The effects of annealing temperature and annealing time to the crystallization behavior of films were studied. The crystallization of thin film started at about $600^{\circ}C$. The adequate crystallization was gotten at the temperature of $650^{\circ}C$ when the annealing time is 0.5 hour or at the temperature of $600^{\circ}C$ when the annealing time is long as 6 hours.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.04b
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• pp.53-53
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• 2002

본 연구에서는 산화텅스텐($WO_3$) 분말을 이용하여 여러 금속 기판에 텅스텐 박막을 코팅하는 방법에 관한 연구를 수행하였다. 본 연구에서 언급되는 W 코팅은 Lee 등이 보고한 W, Cu 산화물을 이용하여 W-Cu 복합분말을 제조하는 것으로부터 아이디어가 출발되었으며, 본 연구의 결과는 기존의 6불화 텅스텐 가스($WF_6$) 를 열 분해하여 증착시키는 화학증착법(CVD: chemical vapor deposition)과 순수 텅스텐 target을 sputtering하여 증착시키는 물리증착법(PVD: physical vapor deposition)과 달리, 산화텅스텐 분말, 금속 기판, 및 수소 가스만을 사용하기 때문에 경제적으로 큰 장점이 있는 새로운 코팅법의 하나로 연구되었다. 본 연구에서는 새로운 코팅법의 기구와 여러 금속에서 코팅되는 W의 코팅 현상 등에 대해 간단히 언급하고자 하였다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.7
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• pp.387-394
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• 2004

Diamond films were deposited on the cemented tungsten carbide WC-Co cutting insert substrates by using both microwave plasma chemical vapor deposition(MWPCVD) and radio frequency plasma chemical vapor deposition (RFPCVD) from $CH_4$$-H_2$$-O_2$ gas mixture. Scanning electron microscopy and X-ray diffraction techniques were used to investigate the microstructure and phase analysis of the materials and Raman spectrometry was used to characterize the quality of the diamond coating. Diamond films deposited using MWPCVD from $CH_4$$-H_2$$-O_2$ gas mixture show a dense, uniform, well faceted and polycrystalline morphology. The compressive stress in the diamond film was estimated to be (1.0∼3.6)$\pm$0.9 GPa. Diamond films which were deposited on the WC-Co cutting insert substrates by RFPCVD from $CH_4$$-H_2$$-O_2$ gas mixture show relatively good adhesion, very uniform, dense and polycrystalline morphology.

• Journal of the Korean Vacuum Society
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• v.1 no.3
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• pp.376-381
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• 1992

Tungsten silicide films were deposited on the highly phosphorus-doped poly Si/SiO2/Si substrates by Low Pressure Chemical Vapor Deposition. They were heat treated in different conditions. XTEM, SIMS and high frequency C-V analysis were conducted for characterization. It can be concluded that outdiffusion of phosphours impurity throught the silicide films lead to its depletion in the poly-Si gate region near the gate oxide, resulting in loss of capacitance and increase of effective gate oxide thickness.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.318-326
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• 1996

This study is to investigate a chemical vapor deposition technique of copper film which is expected to be more useful as metallizations of microcircuit fabrication. An experimental equipment was designed and set-up for this study, and a Cu-precursor used that is a metal-organic compound, named (hfac)Cu(I)VTMS ; (hevaflouoroacetylacetonate trimethyvinylsilane copper). Base pressure of the experimental system is in $10^{-6}$ Torr, and the chamber pressure and the substrate temperature can be controlled in the system. Before the deposition of copper thin film, tungsten or titanium nitride film was deposited onto the silicon wafer. Helium has been used as carrier gas to control the deposition rate. As a result, deposition rate was measured as $1,800\;{\AA}/min$ at $220^{\circ}C$ which is higher than the results of previous studies, and the average surface roughness was measured as about $200\;{\AA}$. A deposition selectivity was observed between W or TiN and $SiO_{2}$ substrates below $250^{\circ}C$, and optimum results are observed at $180^{\circ}C$ of substrate temperature and 0.8 Torr of chamber pressure.