• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1056-1063
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• 2006

Thermal evaporated 10 nm-Ni/l nm-Ir/(or polycrystalline)p-Si(100) and 10 nm-$Ni_{50}Co_{50}$/(or polycrystalline)p-Si(100) films were thermally annealed using rapid thermal annealing fur 40 sec at $300{\sim}1200^{\circ}C$. The annealed bilayer structure developed into Ni(Ir or Co)Si and resulting changes in sheet resistance, microstructure, phase and composition were investigated using a four-point probe, a scanning electron microscopy, a field ion beam, an X-ray diffractometer and an Auger electron spectroscope. The final thickness of Ir- and Co-inserted nickel silicides on single crystal silicon was approximately 20$\sim$40 nm and maintained its sheet resistance below 20 $\Omega$/sq. after the silicidation annealing at $1000^{\circ}C$. The ones on polysilicon had thickness of 20$\sim$55 nm and remained low resistance up to $850^{\circ}C$. A possible reason fur the improved thermal stability of the silicides formed on single crystal silicon substrate is the role of Ir and Co in preventing $NiSi_2$ transformation. Ir and Co also improved thermal stability of silicides formed on polysilicon substrate, but this enhancement was lessened due to the formation of high resistant phases and also a result of silicon mixing during high temperature diffusion. Ir-inserted nickel silicides showed surface roughness below 3 nm, which is appropriate for nano process. In conclusion, the proposed Ir- and Co- inserted nickel silicides may be superior over the conventional nickel monosilicides due to improved thermal stability.

• Korean Journal of Materials Research
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• v.6 no.8
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• pp.779-785
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• 1996

Thin $700^{\circ}C$films were formed through layer inversion of Co/Nb bilayer during rapid thermal annealing(RTA). The Nb interlayer seems to effectively prevent over-consumption of Si and to control the silicidation reaction by forming Co-Nb intermetallic compounds and removing the native oxide formed on Si substrate which interferes the uniform Co-Si interaction. The final layer structure of the Co/Nb bilayer after $700^{\circ}C$ RTA was found to be ${Nb}_{2}{O}_{3}$/${Co}_{2}$Si.CoSi/${NbCo}_{x}$/Nb(O, C)/${CoSi}_{2}$/ Si. The layer inversion and the formation of a stable CoSi, phase occurred above $700^{\circ}C$, and the Nb silicides were not found at any annealing temperature. These may be due to the formation of very stable Co-Nb intermetallic compounds and Nb oxides which limit the moving of Co and Si.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.5
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• pp.94-99
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• 2004

This study was carried out to find out what is the optimum conditions for RAPD of Zelkova serata. We changes the factors what affect to PCR band patterns, as a result, we established the optimum conditions as follows; template DNA 100mg, Primer 0.25uM, dNTP 100mM, Taq polymerase 1.0u, and total reaction volume was filled up to 10uL with distilled water. As the amount of primers went higher, PCR reaction rates were lowered. This reason was cause by exhaustion of primers during initial reaction. The amount of dNTP didn't showed noticable differtations between the range, but the optimum amount was 100mM for efficiency. Taq polymerase 1.0 unit was the best in the range. As the concentration of polymerase were increased, many non-specific bands were appeared, In primer selection, most Openron Random Primers are amplified in this experiment. The primers GC contents were 60, and set A, B, C, D, E, X were tested. Thermal cycler(ASTEC PC808, Japan) condition was, $95^{\circ}C$, 5min, initial denaturation, $94^{\circ}C$, 20sec, denaturation, $37^{\circ}C$, 40sec, annealing, $72^{\circ}C$, 1min, extention, 45cycle repeated and final extention $72^{\circ}C$10min.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.403-411
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• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.146-149
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• 2002

The aim of stereotactic radiosurgery(SRS) is to deliver a high dose to a target region and a low dose to critical organ through only one or a few irradiation. To satisfy this aim, optimized irradiating conditions must be searched in the planning. Thus, many mathematical methods such as gradient method, simulated annealing and genetic algorithm had been proposed to find out the conditions automatically. There were some limitations using these methods: the long calculation time, and the difficulty of unique solution due to the different shape of tumor. In this study, optimization protocol using ideal models and data base was proposed. Proposed optimization protocol constitutes two steps. First step was a preliminary work. Some possible ideal geometry shapes, such as sphere, cylinder, cone shape or the combination, were assumed to approximate the real tumor shapes. Optimum variables such as isocenter position or collimator size, were determined so that the high dose region could be shaped to fit ideal models with the arrangement of multiple isocenter. Data base were formed with those results. Second, any shaped real targets were approximated to these models using geometry comparison. Then, optimum variables for ideal geometry were chosen from the data base predetermined, and final parameters were obtained by adjusting these data. Although the results of applying the data base to patients were not superior to the result of optimization in each case, it can be acceptable as a starting point of plan.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.290-293
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• 2003

Ohmic contact characteristics of Al ion implanted n-type SiC wafer were investigated. Al ions implanted with high dose to obtain the final concentration of $5{\times}10^{19}/cm^3$, then annealed at high temperature. Firstly, B ion ion implanted p-well region were formed which is needed for fabrication of SiC devices such as DIMOSFET and un diode. Secondly, Al implanted high dose region for ohmic contact were formed. After ion implantation, the samples were annealed at high temperature up to $1600^{\circ}C\;and\;1700^{\circ}C$ for 30 min in order to activate the implanted ions electrically. Both the inear TLM and circular TLM method were used for characterization. Ni/Ti metal layer was used for contact metal which is widely used in fabrication of ohmic contacts for n-type SiC. The metal layer was deposited by using RF sputtering and rapid thermal annealed at $950^{\circ}C$ for 90sec. Good ohmic contact characteristics could be obtained regardless of measuring methods. The measured specific contact resistivity for the samples annealed at $1600^{\circ}C\;and\;1700^{\circ}C$ were $1.8{\times}10^{-3}{\Omega}cm^2$, $5.6{\times}10^{-5}{\Omega}cm^2$, respectively. Using the same metal and same process of the ohmic contacts in n-type SiC, it is found possible to make a good ohmic contacts to p-type SiC. It is very helpful for fabricating a integrated SiC devices. In addition, we obtained that the ratio of the electrically activated ions to the implanted Al ions were 10% and 60% for the samples annealed at $1600^{\circ}C\;and\;1700^{\circ}C$, respectively.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.484-492
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• 1998

The formation mechanism of the epitaxial cobalt silicide from Co/Ti/OOO) Si structure has been investigated. The transition temperature of CoSi to CoSi, was found to increase with increasing the Ti interlayer thickness, which may be owing to the occupation of the tetrahedral sites by Ti atoms in the CoSi crystal structure as well as the blocking effect of the Ti interlayer on the diffusion of Co. Also, the Co- Ti-O ternary compound formed at the metal! Si interface at the begining of silicidation, which seems to play an important role in epitaxial growth of Co silicide. The final layer structures obtained after a rapid thermal annealing of the Cot Ti/( 100) Si bi-layer structure turned out to be Ti oxide/Co- Ti-Si/epi-$CoSi_2$/OOO)

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.6
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• pp.244-249
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• 2006

Electrostatic spray pyrolysis, a novel fabrication technique, has been used in this study to prepare calcium phosphate nano powders. Final annealing was done at $400^{\circ}C$ for 30min in air. The hydroxyapatite - forming ability of the annealed powder has been evaluated in Eagle's minimum essential medium solution (MEM). X-ray diffraction analysis, field emission - scanning electron microscope, energy dispersive X-ray spectroscope, and Fourier transform infrared spectroscope were used to characterized the annealed powders after immersion in MEM. The powder with an amorphous structure induced hydroxyapatite formation on their surfaces after immersion fer 15 days.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.14-18
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• 2008

Bismuth-substituted yttrium iron garnet(Bi:YIG) films, which show excellent magnetic and magneto-optical properties as well as low optical losses by optimizing their deposition and post-annealing condition, have been attracting great attention in optical device research area. In this study, the Bi:YIG thick films were deposited with the aerosol deposition method for the final purpose of applying them to optical isolators. Since the aerosol deposition is based on the impact adhesion of sub-micrometer particles accelerated by a carrier gas to a substrate, the flow rate of carrier gas, which is in proportion to mechanically collision energy, should be treated as an important parameter. The Bi:YIG($Bi_{0.5}Y_{2.5}Fe_5O_{12}$) particles with $100{\sim}500$ nm in average diameter were carried and accelerated by nitrogen gas with the flow rate of 0.5 l/min${\sim}$10 l/min. The coercive force decreased from 51 Oe to 37 Oe exponentially with increasing gas flow rate. This is presumably due to the fact that the optimal collision energy results in reduction of impurity and pore, which makes the film to be soft magnetically. The saturation magnetization decreased due to crystallographical distortion of the film with increasing gas flow rate.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.545-552
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• 2003

When a Si PIN diode is exposed to fast neutrons, it results in displacement damage to the Si lattice structure of the diode. Defects induced from structural dislocation become effective recombination centers for carriers which pass through the base of a PIN diode. Hence, increasing the resistivity of the diode decreases the current for the applied forward voltage. This paper involves the development of a neutron sensor based on the phenomena of the displacement effect damaged by neutron exposure. The neutron effect on the semiconductor was analyzed. Several PIN diode arrays with various thickness and cross-section area of the intrinsic layer(I layer) were fabricated. Under irradiation tests with a neutron beam, the manufactured diodes have a good linearity to neutron dose and show that the increase of thickness of I layer and the decrease of cross-section of PIN diodes improve the sensitivity. Newly developed PIN diodes with thicker I layer and various cross section, were retested and then showed the best neutron sensitivity at the condition that the I layer thickness was similar to a side length. On the basis of two test results, final discrete PIN diodes with a rectangular shape were manufactured and the characteristics as neutron detectors were analyzed through the neutron beam test using on-line electronic dosimetry system. Developed PIN diode shows a good linearity as dosimetry in the range of 0 to 1,000cGy(Tissue) and its neutron sensitivity is 13mV/cGy at constant current of 5mA, that is three times higher than that of commercially available neutron detectors. And the device shows little dependency on the orientation of the neutron beam and a considerable stability in annealing test for a long period.