• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.418-418
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• 2012

Synthesis of nanocrystalline diamond powder was investigated via a gas-to-particle scheme using the hot filament chemical vapor deposition. Effect of substrate surface seeding by nano diamond powder, and that of the electrical conductance of the substrate were studied. The substrate temperature, methane content in the precursor gas, filament-substrate distance and filament temperature were $670^{\circ}C$, 5% methane in hydrogen, 10 mm and $2400^{\circ}C$, respectively. The powder formation by gas-to-particle mechanism were greatly enhanced by the substrate seeding by the nano diamond powder. It was attributed to the removal of the electrostatic force between the substrate and the seeded nano diamond particle by the thermal electron shower from the hot filament, via the depolarization of the substrate surface or the attached diamond powder and subsequent levitation into the gas phase to serve as the gas-phase nucleation site. The powder formation was greatly favoured by the conducting substrate relative to the insulating substrate, which proved the actual effect of the electric static force in the powder formation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.966-972
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• 2010

Single-phase $Sr_2FeMoO_6$ thin films were produced by RF magnetron sputtering for use as electrodes in integrated sensors and found to be good conductors at room temperature. The films were deposited from a powder-type sputtering target under various conditions, and were crystallized by annealing. Elimination of $O_2$ gas during deposition, by the use of a solely Ar sputtering gas under a working pressure as low as possible, and vacuum annealing were important to promote the $Sr_2FeMoO_6$ phase. However, oxygen exclusion from sputtering and annealing was not enough to yield single-phase $Sr_2FeMoO_6$: hydrogen annealing was also required. Film production was optimized by varying the deposition parameters and hydrogen annealing conditions. The film had good electrical conduction, with a low resistivity of $1.6{\times}10^{-2}\Omega{\cdot}cm$ at room temperature.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.425-433
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• 1997

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. MgO(100) was used as a substrate. In order to appreciate stable existing region of Bi 2212 phase with temperature and ozone pressure, the substrate temperature was varied between 655 and 82$0^{\circ}C$ and the highly condensed ozone gas pressure(PO$_3$) in vacuum chamber was varied between 2.0$\times$10$^{-6}$ and 2.3$\times$10$^{-5}$ Torr. Bi 2212 phase appeared in the temperature range of 750 and 795$^{\circ}C$ and single phase of Bi 2201 existed in the lower region than 785$^{\circ}C$. Whereas, PO$_3$dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with T$_{c}$(onset) of about 90 K and T$_{c}$(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as CaCuO$_2$was observed in all of the obtained films.lms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.278-280
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• 2001

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. MgO(100) was used as a substrate. In order to appreciate stable existing region of Bi 2212 phase with temperature and ozone pressure, the substrate temperature was varied between 655 and $820^{\circ}C$ and the highly condensed ozone gas pressure($PO_3$) in vacuum chamber was varied between $2.0{\times}10^{-6}$ and $2.3{\times}10^{-5}$ Torr. Bi 2212 phase appeared in the temperature range of 750 and $795^{\circ}C$ and single phase of Bi 2201 existed in the lower region than $785^{\circ}C$. Whereas, $PO_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with $T_c$(onset) of about 90 K and $T_c$(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as $CaCuO_2$ was observed in all of the obtained films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.278-280
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• 2001

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. The growth rates of the films was set in the region from 0.17 to 0.27 nm/min. MgO(100) was used as a substrate. In order to appreciate stable existing region of Bi 2212 Phase with temperature and ozone pressure, the substrate temperature was varied between 655 and 820$^{\circ}C$ and the highly condensed ozone gas pressure(PO$_3$) in vacuum chamber was varied between 2.0x10$\^$-6/ and 2.3x10$\^$-5/ Torr. Bi 2212 Phase appeared in the temperature range of 750 and 795$^{\circ}C$ and single phase of Bi 2201 existed in the lower region than 785$^{\circ}C$. Whereas, PO$_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with T$\sub$c/(onset) of about 70 K and T$\sub$c/(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as CaCuO$_2$ was observed in all of the obtained films.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.861-869
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• 1994

Chemical vapor deposition using titanium tetra isopropoxide(TTIP) was employed to investigate effects of process parameters on the uniformity of $TiO_{2}$this films deposited on Indium Tin Oxide (ITO)coated glass. Deposition experiments were carried out at temperatures ranging from $300^{\circ}C$ to $400^{\circ}C$ under the pressure of 0.5~2 torrin a cold wall reactor which can handle 200mm substrate. It was found that the growth rate of $TiO_{2}$was closely related to the reaction temperature and the ractant gas compositions. Apparent activation energy for the deposition rate was 62.7lkJ/mol in the absence of $O_{2}$ and 100.4kj/mol in the presence of $O_{2}$, respectively. Homogeneous reactions in the gas phase were promoted when the total pressure of the reactor was increased. Variance in the film thickness was less than a few percent, but at high deposition rates film thickness was less uniform. Effects of reaction temperature on $TiO_{2}$ thin film characteristic was investigated with SEM, XRD and AES.

• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.299-306
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• 1996

We invesgated the fesibility of thin films deposition by pyrolysis of metalorganic precursors using chemical beam deposition (CBD) process. We attempted to understand the effects of deposition variables such as substrate temperature operating pressure effusion cell temperature and H2 partial pressure on the properties of MgF2 grown by CBD. Mg(tfac)2 was used as a precursor. MgF2 thin films were always grown in an amorphous state and crystallized bypost-annealing. he higher the substrate temperature and the lower the operating pressure the less the impurities I the deposited MgF2 thin films. H2 gas has to be supplied for the pyrolitic reaction of Mg(tfac)2 decomposition. MgF2 films annealed in H2 have lower C impurity than those annealed in O2. But their crysatllinity was independent of annealing atmosphere. The optimum conditions for the prepara-tion of MgF2 films by CBD process were as following : The substrate temperature 55$0^{\circ}C$ the operating pressure 10-4 torr; effusion cell temperature 21$0^{\circ}C$ the percentage of H2 100% Post-annealing in H2 gas was required to remove residual carbon and to form MgF2 crystalline phase.

• 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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.5
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• pp.563-572
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• 1998

An experimental study of hot filament chemical vapor deposition(HFCVD) has been carried out for the fabrication of diamond thin film. Of particular interest is the measurement of deposition uniformity on large substrates. Experimental apparatus including a vacuum chamber, heating elements, etc. has been designed and manufactured. Deposition profiles for different pretreatment powders and different flow rates have been measured in conjunction with the measurement of substrate temperature distribution on a large substrate surface. As the flow rate increases, deposition rate increases, however, the crystallinity becomes worse. Higher growth rate has been found on the region closer to the center location where substrate temperature is higher. The crystallinity has been improved as gas flow rate decreases. The growth rate and morphology of deposition were identified by SEM and the existence of diamond phase was proved by Raman spectroscopy.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.148-156
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• 1993

TiN films were deposited onto high speed steel (SKH9) by plasma assisted chemical vapor deposition (PACVD) using a TiCl4/N2/H2/Ar gas mixture at around 50$0^{\circ}C$. The effects of the deposition temperature, R.F. power and TiCl4 concentration on the deposition of TiN and the microhardness of TiN film were investigated. The crystallinity and the microhardness of TiN films were improved with increase of the deposition temperature. Optimum deposition temperature in this study was 50$0^{\circ}C$, because a softening or phase transformation of the substrate occurred over 50$0^{\circ}C$. A large increase of the film growth rate with a strong(200) preferred orientation was obtained by increasing R.F. power. Much chlorine content of about 10at.% was found in the deposited films and resulted in relatively low average microhardness of about 1, 500Kgf/$\textrm{mm}^2$ compared with the theoretical value(~2, 000Kgf/$\textrm{mm}^2$).