• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.277-282
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• 2017

Nickel germanide (NiGe) is one of the most promising alloy materials for source/drain (S/D) of Ge MOSFETs. However, NiGe has limited thermal stability up to $450^{\circ}C$ which is a challenge for fabrication of Ge MOSFETs. In this paper, a novel method is proposed to improve the thermal stability of NiGe using Co interlayer. As a result, we found that the thermal stability of NiGe was improved from $450^{\circ}C$ to $570^{\circ}C$ by using the proposed Co interlayer. Furthermore, we found that current-voltage (I-V) characteristic was improved a little by using Co/Ni/TiN structure after post-annealing. Therefore, NiGe formed by the proposed Co interlayer that is, Co/Ni/TiN structure, is a promising technology for S/D contact of Ge MOSFETs.

• Journal of the Korean institute of surface engineering
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• v.49 no.4
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• pp.382-388
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• 2016

NiO nanoparticles were synthesized by hydrothermal method for the application to ethanol gas sensor. They were composited with $Co_3O_4$ nanoparticles to improve the sensitivity to ethanol gas. Scanning electron microscopy revealed that the synthesized NiO nanoparticles were plate-shaped with the approximate size and thickness of 60 - 120 nm and 20 nm, respectively. On the other hand, $Co_3O_4$ nanoparticles mixed with NiO was observed to be spherical with the size range of 30 - 50 nm. The sensitivities of NiO sensors composited with $Co_3O_4$ nanoparticles at an optimal ratio of 8 : 2 were enhanced to approximately 1.44 - 1.79 times as high as those of as-synthesized NiO sensors for the ethanol concentration of 10 - 200 ppm at $200^{\circ}C$. The mechanism of the improved ethanol gas sensing of the NiO sensors composited with $Co_3O_4$ nanoparticles was discussed.

• Journal of the Korean Magnetics Society
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• v.23 no.5
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• pp.149-153
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• 2013

The electronic structures of $TCr_2O_4$ (T = Fe, Co, Ni) spinel oxides have been investigated by employing synchrotron radiation-based soft X ray absorption spectroscopy (XAS). The measured 2p XAS spectra of transition-metal ions reveal that Cr ions are trivalent ($Cr^{3+}$), and all the T (T = Fe, Co, Ni) ions are divalent ($Fe^{2+}$, $Co^{2+}$, $Ni^{2+}$). It is also found that most of T (T = Fe, Co, Ni) ions occupy the A sites under the tetrahedral symmetry, while Cr ions occupy mainly the B sites under the octahedral symmetry. These findings show that the structures of $TCr_2O_4$ (T = Fe, Co, Ni) are very close to the normal spinel structures. Based on these findings, it is expected that Jahn-Teller (JT) effects are important in $FeCr_2O_4$ and $NiCr_2O_4$. In contrast, $CoCr_2O_4$ maintains the cubic structure without having the JT distortion since both $Cr^{3+}$ and $Co^{2+}$ ions are non-JT ions. This work suggests that the antiferromagnetic interaction between $Cr^{3+}$ and $T^{2+}$ ions plays an important role in determining the magnetic properties of $TCr_2O_4$ (T = Fe, Co, Ni).

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.3
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• pp.217-228
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• 2003

Li 이차 전지 음극용 활물질인 $Co_3O_4$의 초기 충방전 효율을 향상시키기 위해 chemical reduction method나 mechanical milling법을 이용하여 $Co_3O_4$에 Ni을 첨가하여 $Ni-Co_3O_4$, 복합물을 제조하였다. 그 결과 초기 충방전 효율이 약 69%에 불과한 $Co_3O_4$에 비해 mechanical milling법을 이용하여 제조된 $Ni-Co_3O_4$ 복합물은 약 79%이상의 대폭 향상된 초기 충방전 효율 특성을 나타내었다. 하지만 chemical reduction method를 이용하여 제조된 $Ni-Co_3O_4$ 복합물은 약 71%의 초기 충방전 효율 특성만을 나타내었다. SEM 분석을 통해 각 물질의 표면 형상을 관찰한 결과 mechanical milling법과 chemical reduction method를 통해 제조된 $Ni-Co_3O_4$ 복합물에서는 $Co_3O_4$ 표면에 분포된 Ni의 균일성의 차이가 존재하였다. $Co_3O_4$가 $Li_2O$의 분해, 형성에 의해 충방전되고 Ni이 $Li_2O$의 분해를 촉진시키는 효과를 가지고 있음을 고려할 때 이러한 균일성의 차이는 결국 Ni 과 $Co_3O_4$ 사이의 접촉면적의 차이로 이어져 $Ni-Co_3O_4$ 복합물의 초기 충방전 효율 특성이 그 제조 방법에 따라 달라지는 것으로 보인다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5376-5383
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• 2011

The objective of this study is the development of carbon-recycle technology, that converts carbon dioxide captured from flue gas to carbon monoxide or carbon for reuse in industrial fields. It is difficult to decompose $CO_2$ because $CO_2$ is very stable molecule. And then metal oxide was used as an activation agent or catalyst for the decomposition of $CO_2$ at low temperature. Metal oxides, which converts $CO_2$ to CO or C, were prepared using Ni-ferrite by solid state method and hydrothermal synthesis in this study. TPR/TPO and TGA were used as an analysis method to analyze the decomposition characteristics of $CO_2$. As the results, the reduction area of $H_2$ was high value at 15 wt% of NiO and the decomposition area of $CO_2$ was superior capacity at 5 wt% of NiO. However, TGA data showed contrary results that reduction area of $H_2$ was 28.47wt% and oxidation area by $CO_2$ was 26.95wt% at 2.5 wt% of NiO, one of the Ni-ferrite powders synthesized using solid state method. $CO_2$ decomposition efficiency was 94.66% and it is excellent results in comparison with previous studies.

• Proceedings of the Korean Magnestics Society Conference
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• 1996.10a
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• pp.26-27
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• 1996

• Proceedings of the Korean Magnestics Society Conference
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• 1997.11a
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• pp.32-33
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• 1997

• Journal of the Korean Magnetics Society
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• v.16 no.5
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• pp.249-254
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• 2006

CoFeNi alloys are some of the most studied soft magnetic materials because of their superial properties over FeNi alloys as write head core materials in HDD and MEMS. We studied the effect of magnetic property according to size and orientation of crystal for electroplated Co-Fe-Ni alleys. In case of heat treated ternary alloy, it affect the change of crystal size and structure. In this study, it intends to improve the magnetic properties of CoFeNi thin film by heat treatment. Minimized coercivity and increased magnetization are due to heat treatment from $300^{\circ}C\;to\;400^{\circ}C$. As a bcc phase formation, it grow to amount of magnetization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.25-28
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• 1998

Lithiated cobalt and nickel oxides are becoming very attractive as active cathode materials for secondary lithium ion secondary battery. $LiCoO_2$ is easily synthesized from lithium cobalt salts, but has a relatively high oxidizing potential on charge. LiNiOz is synthesized by a more complex procedure and its nonstoichiometry significantly degraded the charge-discharge characteristics. But $LiNiO_2$ has a lower charge potential which increases the system stability. Lithiated cobalt and nickel oxides are iso-structure which make the preparation of solid solutions of $LiNi_{1-x}Co_xO_2$ for O$LiCoO_2 and LiNiO_2$ electrode. The aim of the presentb paper is to study the electrochemical behaviour, as weU as the possibilities for practical application of layered Iithiated nickel oxide stabilized by $Co^{3+}$ substitution as active cathode materials in lithium ion secondary battery.

• Korean Journal of Materials Research
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• v.14 no.11
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• pp.769-774
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• 2004

15 nm-Co/15 nm-Ni/P-Si(100)[Type I] and 15 nm-Ni/15 nm-Co/P-Si(100)(Type II) bilayer structures were annealed using a rapid thermal annealer for 40sec at $700/sim1100^{\circ}C$. The annealed bilayer structures developed into composite NiCo silicides and resulting changes in sheet resistance, composition and microstructure were investigated using Auger electron spectroscopy and transmission electron microscopy. Prepared NiCoSix films were further treated in a sequential annealing set up from $900\sim1100^{\circ}C$ with 30 minutes. The sheet resistances of NiCoSix from Type I maintained less than $7\;{\Omega}/sq$. even at the temperature of $1100{\circ}C$, while those of Type II showed about $5\;{\Omega}/sq$. with the thinner and more uniform thickness. With the additive post annealing, the sheet resistance for all the composite silicides remained small up to $900^{\circ}C$. The proposed NiCoSix films were superior over the conventional single-phased silicides and may be easily incorporated into the sub-0.1 ${\mu}m$ process.