• Korean Journal of Materials Research
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• v.13 no.8
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• pp.503-508
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• 2003

The purpose of this study is to investigate the effect of $V_2$$O_{5}$ addition on the Ag and Cu precipitation in the NiCuZn ferrite layers of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt% $V_2$$O_{5}$ -doped ferrite pastes. With increasing the $V_2$$O_{5}$ content and sintering temperature, Ag and Cu oxide coprecipitated more and more at the polished surface of ferrite layers during re-annealing at $840^{\circ}C$. It was thought that during the sintering process, V dissolved in the NiCuZn ferrite lattice and the Ag-Cu liquid phase of low melting point was formed in the ferrite layers due to the Cu segregation from the ferrite lattice and Ag diffusion from the internal electrode. During re-annealing at $840^{\circ}C$, the Ag-Cu liquid phase came out the polished surface of ferrite layers, and was decomposed into the isolated Ag particles and the Cu oxide phase during the cooling process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.500-501
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• 2005

Aluminum doped zinc oxide films (ZnO:Al) were deposited on glass substrate by DC magnetron sputtering from a ZnO target mixed with 2 wt% $Al_2O_3$. The effects of substrate bias on the electrical properties and film structure were studied. Films deposited with positive bias have been annealed at $600^{\circ}C$ using rapid thermal anneal (RTA) process. The effects of RTA on the evolution of film microstructure are to be also studied using X-ray diffraction, transmission electron microscopy, and atomic force microscopy. Positive bias sputtering may induce lattice defects caused by electron bombardments during deposition. The as-deposited film microstructure evolves from the film with high defect density to more stable film condition. The electrical properties of the films after RTA process were also studied and the results were correlated with the evolution of film microstructures.

• Journal of Surface Science and Engineering
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• v.32 no.3
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• pp.389-392
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• 1999

We employed cobalt-disilicide for high-speed logic devices. We prepared stable and low resistant $CoSi_2$ through typical fabrication process including wet cleaning and rapid thermal process (RTP). We sputtered 15nm thick cobalt on the wafer and performed RTP annealing 2 times to obtain 60nm thick $CoSi_2$. We observed spherical shape voids with diameter of 40nm in the surface and inside $CoSi_2$ layers. The voids resulted in taking over abnormal junction leakage current and contact resistance values. We report that the voids in $CoSi_2$ layers are resulted from surface pits during the ion implantation previous to deposit cobalt layer. Silicide reaction rate around pits was enhanced due to Gibbs-Thompson effects and the volume expansion of the silicidation of the flat active regime trapped dimples. We confirmed that keeping the buffer oxide layer during ion implantation and annealing the silicon surface after ion implantation were required to prevent void defects in CoSi$_2$ layers.

• Korean Journal of Metals and Materials
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• v.47 no.4
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• pp.228-234
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• 2009

It is well known that the formation of $SiO_2$, $Al_2O_3$ and/or other oxides at the steel surface during the annealing process deteriorates the surface quality of galvanized steels. It is important to minimize oxide formation during the annealing process for the superior surface quality of galvanized steels. In order to minimize the oxide formation on the steel surface, antimony was chosen as an alloying element to the commercial steels. Then, the effect of alloying element on the oxidation behavior was investigated. A small amount of antimony was added to two types of steels, one with 0.1% C, 1.0% Si, 1.5% Mn, 0.08% P, and the other with 0.002% C, 0.001% Si, 0.104% Mn, 0.01% P. Then, the oxidation behavior was investigated from $650{\sim}900^{\circ}C$ in the air. The addition of antimony to the steels retarded the outward diffusion of elements during the oxidation, resulting in reduction of the oxidation rate.

• Journal of Practical Engineering Education
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• v.10 no.2
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• pp.125-129
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• 2018

This paper is about the numerical analysis on optimized internal flow of LTP furnace and uniformity of temperature. The LTP Furnace is the device that generates heat by electricity. And performs an annealing function for annealing the silicon wafer in the pre-semiconductor manufacturing process. Especially, the maximum temperature inside the chamber is maintained at a high temperature of about $400^{\circ}C$ to strengthen the wafer. When the process is completed at high temperature, the operation is repeated to reduce the temperature through the heat exchanger and carry it out. From this analysis, the ultimate goal is to derive the optimum design of the insulation volume supply/exhaust structure of the chamber through the flow analysis of the LTPS furnace. And to find cases for curriculum development.

• Current Photovoltaic Research
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• v.11 no.4
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• pp.103-107
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• 2023

A Nickel oxide (NiO_x) thin films were prepared via sol-gel process on a transparent conductive oxide glass substrate. The NiO_x thin films were spin-coated in ambient air and subsequently annealed for 30 minutes at temperatures ranging from 150℃ to 450℃. The structural and optical characteristics of the NiO_x thin films annealed at various temperatures were measured using X-ray diffraction, field emission scanning electron microscopy, and ultraviolet-visible spectroscopy. After optimizing the NiO_x coating conditions, perovskite solar cells were fabricated with p-i-n inverted structure, and its photovoltaic performance was evaluated. NiO_x thin films annealed at 350℃ exhibited the most favorable characteristics as a hole transport layer, resulting in the highest power conversion efficiency of 17.88 % when fabricating inverted perovskite solar cells using this film.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.280-286
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• 2020

Cards made from PVC and PET materials do not oxidize or decompose readily, so they are generally incinerated or landfilled after use and cause pollution problems, such as environmental hormones and combustion gases during incineration. In addition, there is a problem of environmental pollution because they are discarded as semi-permanent refuse without being decomposed at landfill. This study attempted to solve this problem using polylactic acid (PLA), which is a representative biodegradable material as a substitute material that can solve the issues with these cards. On the other hand, when the thin card core sheet is made from only PLA material, the physical properties of the material are insufficient, such as the low temperature impact strength, high temperature stability, and poor bending properties, so its use is limited. To solve this problem, the compositional ratio of PLA was reviewed, and the optimal biodegradable compound composition was determined through an examination of the compositions, such as crystallization nucleating agents, additives, and nano compound technology. The high functionalization as a biodegradable card was verified through a laminating process using annealing technology.

• Journal of Powder Materials
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• v.18 no.6
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• pp.552-561
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• 2011

This study attempted to manufacture a Cu-15 at.%Ga coating layer via the cold spray process and investigated the effect of heat treatment environment on the properties of cold sprayed coating material. Three kinds of heat treatment environments, $5%H_2$+argon, pure argon, and vacuum were used in this study. Annealing treatments were conducted at $200{\sim}800^{\circ}C$/1 hr. With the cold sprayed coating layer, pure ${\alpha}$-Cu and small amounts of $Ga_2O_3$ were detected in the XRD, EDS, EPMA analyses. Porosity significantly decreased and hardness also decreased with increasing annealing temperature. The inhomogeneous dendritic microstructure of cold sprayed coating material changed to the homogeneous and dense one (microstructural evolution) with annealing heat treatment. Oxides near the interface of particles could be reduced by heat treatment especially in vacuum and argon environments. Vacuum environment during heat treatment was suggested to be most effective one to improve the densification and purification properties of cold sprayed Cu-15 at.%Ga coating material.

• Korean Journal of Materials Research
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• v.13 no.5
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• pp.292-296
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• 2003

In an attempt to enhance phase transformation and homogenization of Mn-doped $FeSi_2$, mechanical alloying of elemental powders was applied. Cold pressing and sintering in vacuum were carried out to produce a dense microstructure, and then isothermal annealing was employed to induce a phase transformation to the $\beta$-$FeSi_2$semiconductor. Phase transitions in this alloy system during the process were investigated by using XRD, EDS and SEM. As-milled powders after 100 h of milling were shown to be metastable state. As-sintered iron silicides consisted of untransformed mixture of $\alpha$-$Fe_2$$Si_{5}$and $\varepsilon$-FeSi phases. $\beta$-$FeSi_2$phase transformation was induced by subsequent isothermal annealing at $830^{\circ}C$, and near single phase of $\beta$-$FeSi_2$was obtained after 24 h of annealing. Thermoelectric properties in terms of Seebeck coefficient, and electrical conductivity were evaluated and correlated with phase transformation. Seebeck coefficient electrical resistivity and hardness increased with increasing annealing time due to $\beta$ phase transformation.

• Korean Journal of Materials Research
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• v.24 no.4
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• pp.194-200
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• 2014

Metallic Cr film coatings of $1.2{\mu}m$ thickness were prepared by DC magnetron sputter deposition method on c-plane sapphire substrates. The thin Cr films were ammoniated during horizontal furnace thermal annealing for 10-240 min in $NH_3$ gas flow conditions between 400 and $900^{\circ}C$. After annealing, changes in the crystal phase and chemical constituents of the films were characterized using X-ray diffraction (XRD) and energy dispersive X-ray photoelectron spectroscopy (XPS) surface analysis. Nitridation of the metallic Cr films begins at $500^{\circ}C$ and with further increases in annealing temperature not only chromium nitrides ($Cr_2N$ and CrN) but also chromium oxide ($Cr_2O_3$) was detected. The oxygen in the films originated from contamination during the film formation. With further increase of temperature above $800^{\circ}C$, the nitrogen species were sufficiently supplied to the film's surface and transformed to the single-phase of CrN. However, the CrN phase was only available in a very small process window owing to the oxygen contamination during the sputter deposition. From the XPS analysis, the atomic concentration of oxygen in the as-deposited film was about 40 at% and decreased to the value of 15 at% with increase in annealing temperature up to $900^{\circ}C$, while the nitrogen concentration was increased to 42 at%.