• Journal of the Korean institute of surface engineering
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• v.49 no.2
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• pp.125-129
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• 2016

Anodizing is a technology to generate thicker and high-quality films than natural oxide films by treating metals via electrochemical methods. Electrochemical manufacturing method of nano structure is an efficient technology in terms of cost reduction, high productivity and complicated shapes, which receives the spotlight in diverse areas. Especially, artificial films generated by anodizing technology possess excellent mechanical characteristics including hardness and wear resistance. It is also easy to modify thickness and adjust shape of those artificial films so that they are mainly used in sensors, filters, optical films and electrolytic condensers. In this study, experiment was performed to observe the effect of current density on porous film formation in two-step anodizing for Al alloy. Anodizing process was performed with 10 vol.% sulfuric acid electrolyte while the temperature was maintained at $10^{\circ}C$ using a double beaker. and $10{\sim}30mA/cm^2$ was applied for 40 minutes using a galvanostatic method. As a result, both pore diameters and distances between pores tended to increase as the local temperature and electrolysis activity increased due to the increase in applied current density.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.40-43
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• 2018

Various Ni-doped carbon (C : Ni) thin films were fabricated using different Ni target power densities by unbalanced magnetron sputtering (UBM). The effects of target power density on the structural, physical, surface, and electrical properties of C : Ni films were investigated. The UBM C : Ni thin films exhibited uniformly smooth surfaces. The rms surface roughness and friction coefficient values of the C : Ni films decreased with the increase in target power density. The physical properties of the films such as hardness and elastic moduli increased while their electrical properties such as resistivity decreased with the increase in the target power density. These results show that an increase of the power density leads to an increase in the proportion of Ni and nanocrystallization of the amorphous carbon film; this contributes to the changes observed in the physical and electrical characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.213-213
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• 2010

Magnetic random access memory (MRAM), based on magnetic tunnel junction (MTJ) and CMOS, is one of the best semiconductor memories because it can provide nonvolatility, fast access time, unlimited read/write endurance, low operating voltage and high storage density. For the realization of high density MRAM, the etching of MTJ stack with good properties is one of a key process. Recently, there has been great interest in the MTJ stack using MgO as barrier layer for its huge room temperature MR ratio. The use of MgO barrier layer will undoubtedly accelerate the development of MTJ stack for MRAM. In this study, high-density plasma reactive ion etching of MgO films was investigated in an inductively coupled plasma of $Cl_2$/Ar gas mixes. The etch rate, etch selectivity and etch profile of this magnetic film were examined on vary gas concentration. As the $Cl_2$ gas concentration increased, the etch rate of MgO monotonously decreased and etch slop was slanted. The effective of etch parameters including coil rf power, dc-bais voltage, and gas pressure on the etch profile of MgO thin film was explored, At high coil rf power, high dc-bais voltage, low gas pressure, the etching of MgO displayed better etch profiles. Finally, the clean and vertical etch sidewall of MgO films was achieved using $Cl_2$/Ar plasma at the optimized etch conditions.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.136-140
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• 1999

The stability and response time of $WO_3$ thin films for EC device are critical problems being solved. Those are affected by the species of electrolyte, preparation conditions and fabricating methods of specimen. In this paper, we compared the stabilities of three kinds of tungsten oxide film in electrolyte. Each of three films was prepared by different manufacturing conditions, that is, one is a thermal oxidation film of tungsten metal deposited on pure glass substrate, another is a $WO_3$ film made on ITO glass directly, the other is a thermally oxidized film on tungsten plate. It was observed that thermally oxidized $WO_3$ films has a remarkable stability (the lifetime was above $10^6$ cycle). From these results, we found that the stability was closely related to the stoichiometric bonding between tungsten and oxygen atoms in addition to crystallinity and density of film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.105-108
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• 2002

For fabricating high T$\sub$c/ superconducting deposited film, novel electrophoretic deposition technique applied to deposit surface charged Particles on metal substrate with oxy d.c field has been studied. The electric properties of superconducting film don't improve easily because the particles of deposition film are deposited randomly on substrate and don't make orientation affected to its critical current density. In this paper, we studied conventional electrophoresis in addition to a.c field assisted for the improvement of BSCCO superconducting film with high orientation of deposition particles.

• Journal of radiological science and technology
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• v.13 no.2
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• pp.21-25
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• 1990

This report is study about difference of H-D curve in regular film and ortho type film, and obtained results as follows : 1. In the blue-color emission intensifying screen, ortho type films and in the green-color emission intensifying screens, regular type are decreased in their gradient. 2. When joint use of regular type film and ortho type film, the gradient difference not seen in blue color screen. 3. The gradient difference seen clearly in G4, KM screens(green color emission intensifying). Especially, in part of high film density, the gradient difference are great. So we have to right use of screen and film because not matched used of theare the sensitivity and gradient are decrease.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.497-501
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• 2004

The crystal structure of the GaN film on the AIN buffer layer grown by R. F sputtering with different thickness has been studied using X-ray scattering and transmission electron microscopy(TEM). The interface roughness between the AIN buffer layer and the epitaxial GaN film, due to crossover from planar to island grains, produced edge dislocations. The strain, coming from lattice mismatch between the AIN buffer layer and the epitaxial GaN film, produced screw dislocations. The density of the edge and screw dislocation propagating from the interface between the GaN film and the AIN buffer layer affected the electric resistance of GaN film.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.234-237
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• 2007

Water resistance of three biopolyester films, such as poly-L-lactate (PLA), poly-hydroxybutyrate-co-valerate (PHBV), and Ecoflex, and low density polyethylene (LDPE) film was investigated by measuring contact angle of various probe liquids on the films. The properties measured were initial contact angle of water, dynamic change of the water contact angle with time, and the critical surface energy of the films. Water contact angle of the biopolyester films ($57.62-68.76^{\circ}$) was lower than that of LDPE film ($85.19^{\circ}$) indicating biopolyester films are less hydrophobic. The result of dynamic change of water contact angle also showed that the biopolyester films are less water resistant than LDPE film, but much more water resistant than cellulose-based packaging materials. Apparent critical surface energy for the biopolyester films (35.15-38.55 mN/m) was higher than that of LDPE film (28.59 mN/m) indicating LDPE film is more hydrophobic.

• Corrosion Science and Technology
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• v.12 no.4
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• pp.163-170
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• 2013

In NaCl solutions acidified with $H_2SO_4$, Fe20Cr1.1N alloy showed enhanced pitting corrosion resistance than Fe20Cr alloy. An XPS analysis revealed that the passive film of Fe20Cr1.1N alloy contained higher cationfraction of Cr than that of Fe20Cr alloy, and nitrogen was incorporated into the film. In addition, it was found that the passive film of Fe20Cr1.1N alloy was thinner and had higher oxygen vacancy density than that of Fe20Cr alloy. Based on these observations, it was concluded that the chemical composition was the determining factor for the protectiveness of the passive film of Fe20Cr based alloy in dilute $H_2SO_4$ solution.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.8
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• pp.530-534
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• 2017

Transparent film heaters employing silver nanowires (Ag NWs) have attracted increasing attention because of their widespread applications. However, the low thermal resistance of Ag NWs limits the maximum operating temperature of the Ag NW film heater. In this study, Ag NW film heaters with high mechanical and thermal stability were successfully developed. The thermal power-out characteristics of the Ag NW heaters were investigated as a function of the Ag NW density. The results revealed that the prepared flexible Ag NW heater possessed high thermal stability over $190^{\circ}C$ owing to ZnO encapsulation. This indicates that the Ag NW film with excellent thermal stability have remarkably high potential for use as electrodes in film heaters operating at high temperatures.