• Resources Recycling
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• v.26 no.6
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• pp.84-90
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• 2017

The electro-refining process was performed to recovery high purity copper from low grade copper containing sludge in sulfuric acid. The surface morphologies and roughness of electro-refining copper were analyzed with variation of the type and concentration of organic additives, the best surface morphology was obtained 5 ppm of the gelatin type and 5 to 10 ppm of the thiol type organic additive. The crude metal consisted of copper with 86.635, 94.969 and 99.917 wt.%, several impurity metals of iron, nickel, cobalt and tin by pyro-metallurgical process. After electro-refining process, the purity of copper increases to 3N or 4N grade. The impurity concentrations and copper purities of copper crude metals, electrolyte and electro-refining copper were analyzed using ICP-OES, the electro-refining time and purity of copper crude metal to recover 4N grade copper were deduced.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.2 s.31
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• pp.29-35
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• 2004

Hafnium-oxide gate dielectric films deposited by a metal organic chemical vapor deposition technique on a $N_2-plasma$ treated SiNx and a hydrogen-terminated Si substrate have been investigated. In the case of $HfO_2$ film deposited on a hydrogen-terminated Si substrate, suppressed crystallization with effective carbon impurity reduction was obtained at $450^{\circ}C$. X-ray photoelectron spectroscopy indicated that the interface layer was Hf-silicate rather than phase separated Hf-silicide and silicon oxide structure. Capacitance-voltage measurements show equivalent oxide thickness of about 2.6nm for a 5.0 nm $HfO_2/Si$ single layer capacitor and of about 2.7 nm for a 5.7 nm $HfO_2/SiNx/Si$ stack capacitor. TEM shows that the interface of the stack capacitor is stable up to $900^{\circ}C$ for 30 sec.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.6
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• pp.34-41
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• 1984

MOEN/MO double layer which is to be used It)r the RMOS (refractory metal oxide semiconductor) gate material has been fabricated by means of low temperature reactive sputtering in N2 and Ar mixture. Good Mo2N film was obtained in the volumetric mixture of Ar:N2=95:5. The sheet resistance of the fabricated Mo7N film was about 1.20 - 1.28 ohms/square, which is about an order of magnitude lower than that of polysilicon film, and this would enable to improve the operational speed of devices fabricated with this material. When PSG (phosphorus silicate glass) was used as impurity diffusion source for the source and drain of the RMOSFET in the N2 atmosphere at about 110$0^{\circ}C$, the Mo2N was reduced to Mo resulting in much smaller sheet resistance of about 0.38 ohm/square. The threshold voltage of the RMOSFET fabricated in our experiment was - 1.5 V, and both depletion and enhancement mode RMOSFETs could be obtained.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.348-352
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• 2007

In submicron processes, the feature size of ULSI devices is critical, and it is necessary both to reduce the RC time delay for device speed performance and to enable higher current densities without electromigration. In case of contacts between semiconductor and metal in semiconductor devices, it may be very unstable during the thermal annealing process. To prevent these problems, we deposited tungsten carbon nitride (W-C-N) ternary compound thin film as a diffusion barrier for preventing the interdiffusion between metal and semiconductor. The thickness of W-C-N thin film is $1,000{\AA}$ and the process pressure is 7mTorr during the deposition of thin film. In this work we studied the interface effects W-C-N diffusion barrier using the XRD and 4-point probe.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.162-162
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• 2012

Sub 100 nm의 Complementary Metal-Oxide-Semiconductor (CMOS) 소자를 구동하기 위해서는 2.0 nm 이하의 $SiO_2$ oxide에 해당하는 전기적 특성이 요구된다. 그러나 2.0 nm 이하의 $SiO_2$에서는 누설 전류가 너무 크기 때문에 이를 대체하기 위해서 유전 상수 (dielectric permittivity)가 높은 $HfO_2$ (${\varepsilon}=25$), $Al_2O_3$, $HfO_2/Al_2O_3$ laminate 등의 high-k dielectric 물질들이 연구되고 있다[1]. High-k dielectric 물질의 전기적 특성은 박막 조성, 두께 및 전극과의 계면에 생성되는 계면 층이나 불순물(Impurity) 거동에 크게 의존하므로 High-k dielectric/전극(Metal or Si) 구조에서 조성 및 불순물의 거동에 대한 정확한 평가가 주요 쟁점으로 부각되고 있다. 이를 평가하기 위해 일반적으로 $Ar^+$ ion에 의한 depth profiling 분석이 진행되나 Oxygen 원자의 선택적 식각에 기인된 분석 깊이 분해능(Depth Resolution) 왜곡으로 계면 층의 형성이나 불순물의 거동을 정확하게 평가할 수 없다. 이러한 예로는 $Ta_2O_5$ 및 $SrBi_2Ta_2O_9$와 같은 다 성분 계 산화막에 $Ar^+$ ion 주사 시 발생하는 선택적인 식각(Preferential Sputtering) 때문에 박막의 실제 조성 및 거동을 평가하는 것은 어렵다고 보고된 바 있다[2,3]. 본 연구에서는 $90{\AA}$인 적층 $Hf_xO_y/Al_xO_y/Hf_xO_y$ 구조에서의 불순물 거동 분석 능력 확보 상 주요 인자인 깊이 분해능 개선을 Secondary Ion Mass Spectroscopy(SIMS)의 primary ion 종, impact energy 및 주사 각도를 변화시켜 ~1 nm 수준까지 구현하였다. 이러한 분석 깊이 분해능의 개선은 Low Impact Energy, 입사 이온의 glancing angle 및 Cluster ion 적용에 의존하며 이들 요인의 효과에 대해 비교/고찰하고자 한다.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.151-158
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• 2002

The hydorgen storage alloys were produced by melting in arc melting furnace and then solution heat treated at $1,100^{\circ}C$ followed by pulverization. The chemical analysis on the samples showed that the major elements of misch metal(Mm) were La, Ce, Pr and Nd with impurity less than 1wt.%. X-ray diffraction indicated that the structure for these samples were a single phase of hexagonal with $CaCu_5$ type. Compared to the initial particle size $100{\sim}110{\mu}m$, the many fine cracks were found and particle size decreased to $14{\mu}m$ for $MmNi_{4.5}Mn_{0.5}$ after hydriding/dehydring test run. To activate the sample the vessel filled with hydrogen storage alloys was first evacuated for for at $70^{\circ}C$ and then treated for 10.5hr under hydrogen pressure of 20atm for $MmNi_{4.5}Mn_{0.5}$ alloy. The experimental data showed that the hydrogen storage alloy of $MmNi_{4.5}Mn_{0.5}$ had superior adsorption and description properties within a temperature rang of $40^{\circ}C{\sim}80^{\circ}C$ and also they had a good P-C-T curve.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.23-32
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• 1998

Al2O3/Al composites were produced by immersing the sintered silica preform in molten aluminum which contained magnesium as impurity. Three distinct regions existed in the penetration behavior of molten me-tal with changing the reaction temperature. These regions are denoted as low temperature regime(75$0^{\circ}C$-85$0^{\circ}C$) intermediate regime(90$0^{\circ}C$-95$0^{\circ}C$) and high temperature regime(100$0^{\circ}C$$\leq$) In the low temperature regime the penetration speed of molten aluminum increased with increasing reaction temperature whereas it decreased in the intermediate regime due to the phase transition of alumina formed by displacement reac-tion. In the high temperature regime the penetration speed of molten aluminum was the highest at 100$0^{\circ}C$ which was 3.6 mm/hr But above 105$0^{\circ}C$ molten aluminum did not penetrate into the silica preform because of the formation of a dense spinel layer at the preform surface by magnesium in molten Al.

• Journal of IKEEE
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• v.21 no.1
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• pp.96-99
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• 2017

In this study the influence of the random dopant fluctuation (RDF) depending on the halo and LDD implantations for the metal-oxide-semiconductor field effect transistor is investigated through the 3D atomistic device simulation. For accuracy in calculation, the kinetic monte carlo method that models individual impurity atoms and defects in the device was applied to the atomistic simulation. It is found that halo implantation has the greater influence on RDF effects than LDD implantation; three-standard deviation of $V_{TH}$ and $I_{ON}$ induced by halo implantation is about 6.45 times and 2.46 times those of LDD implantation. The distributions of $V_{TH}$ and $I_{ON}$ are also displayed in the histograms with normal distribution curves.

• Resources Recycling
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• v.22 no.4
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• pp.3-11
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• 2013

The recovery of molybdenum and vanadium from acid leaching solutions of spent catalysts using solvent extraction has been investigated. Among various acid leaching solutions, sulfuric acid solution is found to be adequate for the recovery of these two metals. The extraction and stripping behavior of the two metals in the absence and presence of other impurity metals by various types of extractants such as cationic, solvating, amine and a mixture of cationic and solvating extractants was discussed. Each type of extractants has advantage and disadvantage in terms of the possibility of separation and of forming a third phase. Among the various types of extractants, a mixture of cationic and solvating extractants seems to be the most promising extractant system for the separation of Mo and V from the acid leaching solutions of spent catalysts.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.550-553
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• 2003

The genes of GFPuv and Cytochrome c-552 were amplified by using PCR, and then, fused each other. Fusion gene of GFPuv and Cytochrome c-552 was inserted into the pTrcHis B vector and transferred to E. coli. A fusion protein of GFPuv and Cytochrome c-552 was expressed in JM109 and BL21. This fusion protein was composed of a His-tag for the rapid one-step purification using an immobilized metal affinity chromatography.