• Journal of Magnetics
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• v.6 no.1
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• pp.23-26
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• 2001

Nano-crystalline hexaferrite $BaFe_{12}O_{19}$(BaM) thin films have been prepared by the sol-gel method. A solution of Ba-nitrate and Fe-nitrates was dissolved in solvent with the stoichiometric ratio Ba/Fe=1/10. Films were spin-coated onto $SiO_2$Si substrates, dried and then heated in air at various temperatures. In films prepared at a drying temperature $T_d=250^{\circ}C$ and a crystallizing temperature 650${\circ}C$, single-phase BaM was obtained. High coercivities were obtained in these nano-crystalline thin films, 4~5.5 kOe for hexaferrite. Polycrystalline BaM/$SiO_2$/Si(100) thin films were characterized by Rutherford backscattering (RBS), thermogravimetry (TGA), differential thermal analysis (DTA), x-ray diffraction (XRD), and vibrating sample magnetometry (VSM), as well as Fourier transform infrared spectroscopy (FTIR). The perpendicular coercivity $H_{C\bot}$ and in-plane coercivity $H_{CII}$ after annealing at 650${\circ}C$ for 2 hours were 4766 Oe and 4480 Oe, respectively, at room temperature, under a maximum applied field of 10 kOe.

• Journal of Magnetics
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• v.20 no.4
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• pp.336-341
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• 2015

MnBi alloys were fabricated by arc melting and annealing at 573 K. The heat treatment enhanced the content of the low-temperature phase (LTP) of MnBi up to 83 wt%. The Bi-excess assisted LTP MnBi alloys were used in the hybridization with the Nd-Fe-B commercial Magnequench ribbons to form the hybrid magnets (100-x)NdFeB/xMnBi, x = 20, 30, 40, 50, and 80 wt%. The as-milled powder mixtures of Nd-Fe-B and MnBi were aligned in a magnetic field of 18 kOe and warm-compacted to anisotropic and dense bulk magnets at 573 K by 2,000 psi for 10 min. The magnetic ordering of two hard phase components strengthened by the exchange coupling enhanced the Curie temperature ($T_c$) of the magnet in comparison to that of the powder mixture sample. The prepared hybrid magnets were highly anisotropic with the ratio $M_r/M_s$ > 0.8. The exchange coupling was high, and the coercivity $_iH_c$ of the magnets was ~11-13 kOe. The maximum value of the energy product $(BH)_{max}$ was 8.4 MGOe for the magnet with x = 30%. The preparation of MnBi alloys and hybrid magnets are discussed in details.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.109-118
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• 2004

No.2 PCM (Pickling and tandem cold rolling mill) at Pohang works was revamped in 2003. The purpose of this project is to produce carbon and stainless steel using conventional carbon production process, rolling and annealing. This paper introduces the applied facilities and technologies of PCM which are used in production of carbon and stainless steel. To realize the main purpose of this project, POSCO have developed laser weld technology in normal carbon and special steel (stainless, high carbon and high silicon). And this report describes the method which is developed to get down the surface defect of stainless 400 series. After revamping, No.2 PCM can have competitive power in this field and can supply the special steel using carbon rolling process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.5
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• pp.394-398
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• 2007

A simple doping method to fabricate a very thin channel body of the nano-scaled n-type fin field-effect-transistor (FinFET) by arsenic solid-Phase-diffusion (SPD) process is presented. Using the As-doped spin-on-glass films and the rapid thermal annealing for shallow junction, the n-type source-drain extensions with a three-dimensional structure of the FinFET devices were doped. The junction properties of arsenic doped regions were investigated by using the $n^+$-p junction diodes which showed excellent electrical characteristics. The n-type FinFET devices with a gate length of 20-100 nm were fabricated by As-SPD and revealed superior device scalability.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.4
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• pp.247-249
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• 2016

In this study, we investigated the color change of the normal light gray granite as the high value color granite. By coating the metal catalyst liquid on the surface of granite stone, the metal particles were penetrated into the granite and the color of granite was changed permanently through the annealing treatment. To increase penetration depth into the granite, we used DC (direct current) bias. Two kinds of bias were used such as DC bias and pulse DC bias. And the penetration time was changed as 30 and 60 min. In all cases, the color granite were successfully obtained. Regardless of the catalyst reaction time, the penetration depth was increased by using the bias treatment. We obtained a penetration depth of 21 mm with the DC pulse bias during 60 min.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.287.1-287.1
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• 2014

본 연구에서는 현재 디스플레이에서 가장 널리 이용되는 저온 polycrystalline silicon (poly-Si)의 결정화 방법에 따른 thin-film transistor (TFT)의 전기적 특성을 분석하였다. 분석에 이용된 결정화 방식은 Excimer Laser Annealing (ELA)와 Metal Induced Crystallization (MIC)이다. ELA와 MIC TFTs의 전기적 특성 측정을 통한 분석결과 ELA와 MIC poly-Si TFTs의 전기적 특성 [field-effect mobility (${\mu}_{FE}$), on/off current ratio ($I_{ON}/I_{OFF}$), sub-threshold swing (SS)]은 큰 차이는 없지만, ELA를 이용한 poly-Si TFT의 전기적 특성이 조금 우수하다. 하지만, MIC poly-Si TFT의 경우 threshold voltage ($V_{TH}$)가 0V에 보다 가까울 뿐만 아니라, 전기적 스트레스를 통한 신뢰성 확인 시 ELA poly-Si TFT보다 조금 더 안정적이다. 이는 ELA의 경우 좁은 면에 선형 레이저 빔으로 조사하면서 생기는 hill-lock의 영향으로 표면이 거칠고 균일하지 못하여 바이어스 인가시 생기는 문제이다. 또한 MIC는 금속 촉매를 이용해 결정립 경계를 확장하고 결정 크기를 키워 대면적화에 유리하다. Thermal Stress에서는 (from 293K to 373K) TFT에 점차 높은 온도를 가하자 MIC poly-Si TFT의 경우 off 상태에서 누설 전류 값이 증가하며 열에 민감한 반응을 보이는 것을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.10-13
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• 2005

$Sr_{0.6}Ba_{0.4}Nb_{2}O_{6}$, hereafter SBN60, thin films of 300 nm thickness were deposited using ion beam sputtering technique, in which sintered ceramic target of the same composition was utilized and the $Ar:O_{2}$ gas ratio was controlled during deposition onto $Pt(100)/TiO_{2}/SiO_{2}/Si$ substrate. Crystallization and orientation behavior as well as electrical properties of the films were examined after annealing treatment at $650{\sim}800{\cric}C$. It was found that the film orientation was dependent upon $Ar:O_{2}$ratio, in which strong (00l) orientation was developed when the gas ratio was about 1:4 at $4.3{\times}10^{-4}$ torr. Typical remanent polarization (2Pr), the coercive field (Ec) and the dielectric constant of Pt/SBN60/Pt thin film capacitor were approximately $10{\mu}C/cm^{2}$, 60 kV/cm, and 615, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.5
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• pp.370-375
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• 2001

PZT thin films (3500${\AA}$) ahve been prepared onto Pt/Ti/corning glass (1737) substrates with a RF magnetron sputtering system using Pb$\sub$1.50/(Zr$\sub$0.52/,Ti$\sub$0.48)O$_3$ ceramic target. We used two-step annealing techniques, PZT thin films were grown at a 300$^{\circ}C$ substrate temperature and then subjected to an RTA treatment. In case of 500$^{\circ}C$ RTA temperature show pyrochlore phase. The formation of Perovskite phase started above 600$^{\circ}C$ and PZT thin films generated (101) preferred orientation. As the RTA time and temperature increased, crystallization of PZT films were enhanced. The PZT capacitors fabricated at 650$^{\circ}C$ for 10 minutes RTA treatment showed remanent polarization 30 ${\mu}$C/$\textrm{cm}^2$, saturation polarization 42${\mu}$C/$\textrm{cm}^2$, coercive field 110kV/cm, leakage current density 2.83x10$\^$-7/A/$\textrm{cm}^2$, remanent polarization were decreased by 30% after 10$\^$9/ cycles.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.187-191
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• 2014

Indium oxide ($In_2O_3$) nanorods (NRs) which can be expected to increase the device performance in various electronic and electrochemical applications were prepared on carbon fibers via an electrochemical deposition (ED) method. During the ED, the indium hydroxide ($In(OH)_3$) NRs were well grown and firmly attached onto the carbon fibers. After that, they were changed into $In_2O_3$ by dehydration through a thermal annealing. The morphological and structural properties were investigated using field-emission scanning electron microscope images. The crystallinity of as-prepared sample was evaluated by X-ray diffraction. The Fourier transform infrared results confirm that the functional groups are present in the $In_2O_3$ NRs. This facile process of metal oxide nanostructures on carbon fiber can be utilized for flexible electronic and energy related applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.252-252
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• 2011

최근 주목받고 있는 amorphous gallium-indium-zinc-oxide (a-GIZO) thin film transistors (TFTs)는 수소가 첨가된 비정질 실리콘 TFT에 비해 높은 이동도와 뛰어난 전기적, 광학적 특성에 의해 큰 주목을 받고 있다. 또한 넓은 밴드갭을 가지므로 가시광 영역에서 투명한 특성을 보이고, 플라스틱 기판 위에서 구부러지는 성질에 의해 플랫 패널 디스플레이나 능동 유기 발광소자 (AM-OLED), 투명 디스플레이에 응용되고 있다. 뿐만 아니라, 일반적인 Poly-Si TFT는 자체적으로 가지는 결정성에 의해 대면적화 시 균일성이 좋지 못하지만 GIZO는 비정질상 이기 때문에 백플레인의 대면적화에 유리하다는 장점이 있다. 이러한 TFT를 제작하기 전, 전기적 특성에 대한 정보를 얻거나 예측하는 것이 중요한데, 이에 따라 고안된 구조가 바로 metal point contact FET (pseudo FET)이다. pseudo FET은 소스/드레인 전극을 따로 증착할 필요 없이 채널을 증착한 후, 프로브 탐침을 채널의 표면에 적당한 압력으로 접촉시켜 전하를 공급하는 소스와 드레인처럼 동작시킬 수 있다. 따라서 소스/드레인을 증착하거나 lithography와 같은 추가적인 공정을 요구하지 않아 소자의 특성을 보다 간단하고 수월하게 분석할 수 있다는 장점이 있다. 본 연구에서는 p-type 기판위에 100nm의 oxidation SiO2를 게이트 절연막으로 사용하는 a-GIZO pseudo FET를 제작하였다. 소자 제작 후, 열처리 온도에 따른 전기적 특성을 분석하였고, 열처리 조건은 30분간 N2 분위기에서 실시하였다. 열처리 후 전기적 특성 분성 결과, 450oC에서 가장 낮은 subthreshold swing 값과 게이트 전압의 더블 스윕 후 문턱 전압의 변화가 거의 없음을 확인하였다.