• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.1
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• pp.35-40
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• 1997

A new method to form the gate oxide and recrystllize the polycrystalline silicon (poly-Si) active layer simultaneously is proposed and fabricated successfully. During te irradiation of excimer laser, the poly-Si film is recrystallized, while the oxygen ion impurities injected into the amorphous silicon(a-Si) film are activated by laser energy and react with silicon atoms to form SiO2. We investigated the characteristics of the sample fabricated by proposed method using AES, TEM, AFM. The electrical performance of oxide was verified by ramp up voltage method. Our experimental results show that a high quality oxide, a pol-Si film with fine grain, and a smooth and clean interface between oxide and poly-Si film have been successfully obtained by the proposed fabrication method. The interface roughness of oxide/poly-Si fabricated by new method is superior to film by conventional fabrication os that the proposed method may improve the performance of poly-Si TFTs.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.141-144
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• 2000

The slope stability of waste landfill has been a problem in domestic and foreign countries. Waste landfills are being constructed in a reclaimed land or mountainous area. But most of these places are consisted of steep slope and hence it is necessary to use the geosynthetic liners in there. The large size direct shear test(30cm x 30cm) equipment was used to determine the interface friction angles between CCLs and soil & geomembranes. The centrifuge model tests were performed to investigate the slope stability with considering various geosynthetic liners conditions and degree of slope. The results of centrifuge model test indicate that the degree of saturation of GCL, roughness of geomembrane, and slope of landfill have greatly influenced on the slope stability of solid waste landfill.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1061-1064
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• 2003

In this paper, we deposited A1$_2$O$_3$ thin film using atomic layer deposition(ALD) method on Ti and fabricated metal-insulator-metal(MIM) capacitor. In the result of this study, the typical deposition rate was about 1.12$\AA$/cycle. About 30 nm of Ti was consumed during deposition and TiO$_{x}$ was formed at the interface of A1$_2$O$_3$ and Ti. Its surface roughness was 1.54nm. The leakage current density was 1.5 nA/$\textrm{cm}^2$. The temperature coefficient of capacitance(TCC) of MIM capacitor was 41 ppm/$^{\circ}C$ at 1MHz and 100 ppm/$^{\circ}C$ at 100 kHz.z.

• 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.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.1
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• pp.17-26
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• 1998

Cladding of stainless steel on mild steel was prepared by diffusion bonding process. The bond strength increased with an increase of bonding temperature and time. It was also found that the bond strength increased as the surface roughness decreased. After the diffusion bonding of stainless steel-mild steel, the mild steel part near the bonded interface showed higher strength than the base steel due to the migration of chromium and nickel from stainless steel to mild steel. Carbon migration from mild steel gave effect on the formation of chromium carbides at grain boundaries of stainless steel, the fractograpohic features of the imperfectly bonded interface showed rather coarse dimples in the mild steel part and very fine dimples in the stainless steel part.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.125-125
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• 2012

Graphene was epitaxially grown on a 6H-SiC(0001) substrate by thermal decomposition of SiC under ultrahigh vacuum conditions. Using scanning tunneling microscopy (STM), we monitored the evolution of the graphene growth as a function of the temperature. We found that the evaporation of Si occurred dominantly from the corner of the step rather than on the terrace. A carbon-rich $(6{\sqrt{3}}{\times}6{\sqrt{3}})R30^{\circ}$ layer, monolayer graphene, and bilayer graphene were identified by measuring the roughness, step height, and atomic structures. Defect structures such as nanotubes and scattering defects on the monolayer graphene are also discussed. Furthermore, we confirmed that the Dirac points (ED) of the monolayer and bilayer graphene were clearly resolved by scanning tunneling spectroscopy (STS).

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1503-1506
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• 1997

The main fault in this interface is that power cable insulating materials are mainly composed of a double layered structure, XLPE/EPDM laminates in cable joint. In this paper, we instituted the interface of normal and degassed XLPE/EPDM and then investigated the breakdown and conduction characteristics as a function of heat treatment time. The results showed that conduction and breakdown strength was influenced by volatile crosslinking by-products which remained inside the insulating material during the production of XLPE and EPDM, especially during heat treatment process. And micro voids and surface roughness also influenced the conduction current and breakdown strength.

• Electronics and Telecommunications Trends
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• v.3 no.4
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• pp.3-12
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• 1988

Epilayer growing process has been recognized as a key technology for successful GaAs based devices and integrations. These may include HEMT, multiple quantum well structures, band gap engineering, and quantum confinement heterostructures. The fabrication of epilayers in these devices must meet very stringent requirements in terms of crystallinity, composition, film thickness and interface quality. In particular, the quality of interfaces is getting more important because the film thickness, and flatness, roughness and stability at interface of ultrathin films cause critical effects on the device performance. This article reviews the current status of modern epitaxial techniques which have been developed in the last few years. First, the new techniques PLE, GI, MEE, TSL based on MBE technique will be reviewed and their technical importance will be stressed. Secondly, MOMBE, GSMBE, CBE which combine the advantages of MBE and MOCVD will also be discussed. Thirdly, the new sophisticated epitaxial technique, ALE, of which mechanism is totally different from others, will also be reviewed. Finally, areas which should be exploited more extensively to accomplish these techniques will be addressed.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1978-1980
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• 2000

Because the interfaces between two different materials are the weak-link in the underground power transmission systems, they affects the stability of insulation systems. In this paper, Epoxy/EPDM interface is selected and investigated the optimum condition by variation of interfacial conditions such as roughness of surface, spreading of oils, interfacial pressure and temperature. The breakdown times under the constant voltage below the breakdown voltage were also gamed. The breakdown voltage at the after laying time equivalent to is calculated by the V-t characteristic and the inverse power law. When this is done. the characteristic life exponent n is used and the long time breakdown voltage can be evaluated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.84-87
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• 2003

The interfacial diffusion in Fe/Cr/MgO(001) multilayers has been studied using synchrotron x-ray techniques, such as x-ray reflectivity, extended x-ray absorption fine structures (EXAFS), and anomalous x-ray scattering (AXS). The results of x-ray reflectivity indicated that the interfacial roughness of Fe/Cr multilayers with Cr-$4{\AA}$-thick was larger than that with Cr-$4{\AA}$-thick. The results of EXAFS indicated that the Fe element dominantly diffuse into the stable Cr layers at the Fe/Cr interface. The AXS was certified the existence of the interdiffused Fe element in the Cr layers. Our study revealed that the rough interface of the Fe/Cr multilayers was caused by the interfacia diffusion of Fe element into the Cr layers.