• Nuclear Engineering and Technology
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• v.40 no.2
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• pp.99-106
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• 2008

Through mechanical alloying, hot isostatic pressing and hot rolling, a 9%Cr Fe-based oxide dispersion-strengthened alloy sample was fabricated. The tensile strength of the alloy is significantly improved when the microstructure is modified during the post-consolidation process. The alloy samples were strengthened as the cooling rates increased, though the elongation was somewhat reduced. With a cooling rate of $800^{\circ}C/s$ after normalization at $1150^{\circ}C$, the alloy sample showed a tensile strength of 1450 MPa, which is about twice that of the hot rolled sample; however, at $600^{\circ}C$ the tensile strength dramatically decreased to 620 MPa. Optical microscope and transmission electron microscope were used to investigate the microstructural changes of the specimens. The resultant strengthening of the alloy sample could be mainly attributed to the interstitially dissolved nitrogen, the fraction of the tempered martensite, the fine grain and the presence of a smaller precipitate. The decrease in the tensile strength was mainly caused by the precipitation of vanadium-rich nitride.

• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.17-21
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• 2016

EUV (Extreme Ultraviolet) pellicle which protects a mask from contamination became a critical issue for the application of EUV lithography to high-volume manufacturing. However, researches of EUV pellicle are still delayed due to no typical manufacturing methods for large-scale EUV pellicle. In this study, EUV pellicle membrane manufacturing method using not only KOH (potassium hydroxide) wet etching process but also a water bath was suggested for uniform etchant temperature distribution. KOH wet etching rates according to KOH solution concentration and solution temperature were confirmed and proper etch condition was selected. After KOH wet etching condition was set, $5cm{\times}5cm$ SiNx (silicon nitride) pellicle membrane with 80% EUV transmittance was successfully manufactured. Transmittance results showed the feasibility of wet etching method with water bath as a large-scale EUV pellicle manufacturing method.

• Journal of the Korean Vacuum Society
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• v.5 no.1
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• pp.54-61
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• 1996

Indium-tin oxide (ITO) films were deposited on the glass substrate by the reactive -ionized cluster beam deposition(ICBD) method. In the oxygen atmosphere, indium cluster formed through the nozzle is ionized by the electron bombardment and is accelerated to be deposited on the substrate. And tin is simultaneoulsy evaporated from the boron-nitride crucible. The chracteristics of films were examined by the X-ray photoelectron spectroscopy(XPS), glancing angle X-ray diffractrion(GXRD) and the electrical properties. were measured by 4-point-probe and Hall effect measurement system . From the XPS spectrum , it was found that indium and tin atoms combined with the oxygen to form oxide$(In_2O_3, SnO_2)$. In the case of films with high tin-concentration, the GXRD spectra show that the main $In_2O_3$ peak of (222) plane, but also sub peaks((440) peak etc.) and $SnO_2$ peaks were detected. From that results, itis concluded that the heavily dopped tin component (more than 14 at. %) disturbs to form $In_2O_3$(222) phase. Four-point-probe and Hall effect measurement show that, in the most desirable case, the transmittance of the films is more then 90% in visible range and its resistivity is $$\rho$=3.55 \times10^{-4}\Omega$cm and its mobility is $\mu$=42.8 $\textrm{cm}^2$/Vsec.

• Proceedings of the Korean Vacuum Society Conference
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• 1995.06a
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• pp.151-151
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• 1995

Nitrogen implantation process has been applied for improvement of wear resistance of Z Zircaloy-4 fuel cladding materials. Nitrogen was implanted at 120 ke V to a total do range of 1xHP ions/cm2 to 8xlO17 ions/cm2 at various temperatures of 298"C to 676"C. The m microstructure changes by nitrogen implantation were analyzed by using TEM, XRD 뻐d A AES, cmd then wear behavior was evaluated by ball-on-disc wear testings at various loads a and sliding velocity under unlubricated condition. Nitrogen implantation produced ZrNx nitride above 4.37x1017 ions!cm2 as well as heavy d dislocations, which enhanced microhardness of the implanted surface of up to 900 Hk from 2 200 Hk of unimplanted substrate. Hardness was also found to be increased with increasing i implantation temperature and enhanced up to OOOHk at 620 "C. the wear resistance was g greatly improved with increasing total ion do않 as well as implantation temperature. The effective enhancement of wear resistance at high dose and tem야ratures is believed d due to significant hardening associated with high degree of precipitation of Zr nitrides and g generation of prismatic dislocation I$\infty$ps.infty$ps.

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.743-748
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• 2000

Amorphous carbons(neddle cokes), which are used as anode materials for lithium ion secondary batteries, were graphitized or heat-treated at high temperature in $N_2$ atmosphere and in Ar atmosphere, after adding $B_2O_3$. After then, using transmission eletron microscopy, their surface micro-structures and the formations and distributions of the second phases were analyzed. It was studied that such analyzed results were related to the cell capacities and efficiencies.

• Korean Journal of Materials Research
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• v.12 no.1
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• pp.44-47
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• 2002

DV(Discrete Variation)-X${\alpha}$ cluster calculation was employed to calculate the electronic states of ${\gamma}'- Fe_4N$ which was one of iron nitride phases synthesized from plasma ion nitriding to improve surface hardness and wear resistance. The result of calculated electron density of states for Fe was similar to the result of band calculation. The cluster used for calculation of electronic states of ${\gamma}'-Fe_4N$ was based on $Fe_{14}N$ cluster which comprises 15 atoms. Finally the electronic states of ${\gamma}'- Fe_4N$ such as net-charge, band order, energy level, electron wave-function, and contour map for electron density were derived by the calculation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.37-40
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• 1999

For the first time, charge trapping nonvolatile semiconductor memories with the deoxidized oxynitride gate dielectric is proposed and demonstrated. Gate dielectric wit thickness of less than 1 nm have been grown by postnitridation of pregrown thermal silicon oxides in NO ambient and then reoxidation. The nitrogen distribution and chemical state due to NO anneal/reoxidation were investigated by M-SIMS, TOF-SIMS, AES depth profiles. When the NO anneal oxynitride film was reoxidized on the nitride film, the nitrogen at initial oxide interface not only moved toward initial oxide interface, but also diffused through the newly formed tunnel oxide by exchange for oxygen. The results of reoxidized oxynitride(ONO) film analysis exhibits that it is made up of SiO$_2$(blocking oxide)/N-rich SiON interface/Si-rich SiON(nitrogen diffused tunnel oxide)/Si substrate. In addition, the SiON and the S1$_2$NO Phase is distributed mainly near the tunnel oxide, and SiN phase is distributed mainly at tunnel oxide/Si substrate interface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.235-238
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• 2004

본 연구는 반도체소자 제조공정에 적용되는 CMP공정 중 LPP(Landing Plug Poly) Contact간의 소자 분리를 위해 진행되는 LPP CMP의 후 세정 과정에서 유발되는 방사형 Defect 제거에 관한 내용이다. 방사형 Defect은 LPP CMP 후에 노출되는 BPSG, Poly, Nitride Film과 연마재로 사용되는SiO2 입자, 후 세정과정에서 적용되는 SC-1, DHF, $NH_4OH$ Chemical과 Brush와의 상호작용에 의해 발생되며, Cleaning시의 산성 분위기 하에서 각 물질간의 pH와 Zeta Potential의 차이에서 기인한다. 이 Defect을 제거하기 위해 LPP CMP후에 Film 표면에 노출되는 각 물질의 표면 특성과 CMP 후 오염입자의 흡착과 재 흡착에 영향을 미치는 Electrostatic force와 Van der Waals force, PVA Brush에 의한 Mechanical force의 상호작용을 고려하여 최적 후 세정 조건을 제시 하였다.

• Journal of the Korean Ceramic Society
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• v.20 no.1
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• pp.63-69
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• 1983

It is know that $Si_3-N_4$ bonded SiC has almost all the valuable properties needed for the high temperature material and thus has bery wide range of applicability. Si powder and two different sized SiC powder were used as the raw mateials. Specimens were prepared by heating the green compact mode of the raw materials with polyvinyl alcohol binder in the nitrogen atmosphere. The bond-ing of SiC particles is brought about with the formation of reaction bonded silicon nitride phase between the particles he influences of the variation of the relative amounts of the raw materials and the amount of the organic binder on the density and the bend strength of the specimens were investigated. It was shown that the calculation of the amount of the nitridation of Si is somewhat complicated matter since some portion of the organic binder reacts with the Si during the firing process. Fixing the Si amount to 20w/o the distributions of the size of the SiC particles that gives the maximum density and the maximum strnegth were obtained through experiments. It was observed that the two distributions were not equal to each other. As the amount of Si increased the amount of Si reacted with nitrogen and the strength increased. The fracture mode was intergranular for the most part and the transgranular fracture was scarcely observed.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1673-1681
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• 2018

In this paper, the fabrication of a white light-emitting diode (WLED) package capable of producing different color rendering indexes (CRI ($R_a$)) using different types of phosphors (YAG:Ce, Silicate, Nitride, LuAG) for the LEDs is presented. The color quality is evaluated based on the current and temperature variation conditions. The evaluation method for color quality compares the existing CIE 13.3 method and the new IES TM-30-15 method. The CRI ($R_a$) defined in the conventional CIE 13.3 has the disadvantage. This cannot offer any information relevant to the user's preference. However, the newly proposed IES TM-30-15 method suggests the additional measure related to user's preference such as Color Gamut ($R_g$). The present experimental results obtained using the IES TM-30-15 show that the color quality of the WLEDs using green and red phosphors are better than that of the WLEDs using yellow phosphor, but their luminous efficacies are lower. The color quality of WLEDs using green and red phosphors are more stable than that of the WLEDs using yellow phosphor, for current and temperature variations, and it is verified that the phosphor causes this change. The evaluation method for color quality, based on IES TM-30-15, is proved to be capable of overcoming the problems of the existing evaluation methods by this study.