• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.479-486
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• 2007

Four point bending is used to study the dependences of bond strength of benzocyclobutene(BCB) bonded wafers and BCB thickness, the use of an adhesion promoter, and the materials being bonded. The bond strength depends linearly on BCB thickness, due to the thickness-dependent contribution of the plastic dissipation energy of the BCB and thickness independence of BCB yield strength. The bond strength increases by about a factor of two with an adhesion promoter for both $2.6{\mu}m$ and $0.4{\mu}m$ thick BCB, because of the formation of covalent bonds between adhesion promoter and the surface of the bonded materials. The bond strength at the interface between a silicon wafer with deposited oxide and BCB is about a factor of three higher than that at the interface between a glass wafer and BCB. This difference in bond strength is attributed to the difference in Si-O bond density at the interfaces. At the interfaces between plasma enhanced chemical vapor deposited (PECVD) oxide coated silicon wafers and BCB, and between thermally grown oxide on silicon wafers and BCB, 12~13 and $15{\sim}16bonds/nm^2$ need to be broken. This corresponds to the observed bond energies, $G_0s$, of 18 and $22J/m^2$, respectively. Maximum 7~8 Si-O $bonds/nm^2$ are needed to explain the $5J/m^2$ at the interfaces between glass wafers and BCB.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.25-32
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• 2016

The purpose of this study is to evaluate the performance on the compressive bonding shear strength of ultra-high strength steel fiber reinforced cementitous composites(UHSCC). As a result of compressive bonding shear strength through Direct shear test, It was found that the specimen($150{\times}150{\times}150mm$) of NC(Normal concrete) + NC showed similar compressive bonding shear strength at whole experimental level. On the other hand, the specimen of UHSCC + UHSCC showed decrease of compressive bonding shear strength from after 30 minutes of the retarded placement than 0 minute. As a result of analyzing failure mode of bonding interface, It was found that the specimen of NC + NC showed mixed failure at whole experimental level. In case of the specimen of UHSCC + UHSCC, it showed interface failure from the specimen that are 30 minutes, 60 minutes and 90 minutes of delay of concrete placing. As a result of analyzing XRD test in terms of the placement interface on the specimen of NC and UHSCC, relatively much amount of $SiO_2$ was detected from the specimen of UHSCC than that of NC. It is judged that the most of main components of coating film shown in the specimen of UHSCC is $SiO_2$. In conclusion, it is judged that UHSCC which is made from after 30 minutes of delay of concrete placing is unable to be used as structural member because of deterioration of bonding performance. From later study, it is judged that the improvement of bonding performance from the part of cold joint occurrence is necessary through the interface preparation method.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.244-244
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• 2007

• Journal of Magnetics
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• v.17 no.2
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• pp.78-82
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• 2012

CoNiFe(CNF)/$BaTiO_3(BTO)$/CoNiFe(CNF) multilayered thin films were deposited on Pt/Ti/$SiO_2$/Si substrates by using pulsed laser deposition (PLD) system. We fabricated three different thin films of BTO, BTO/CNF and CNF/BTO/CNF for magneto-capacitor and studied their crystalline structure, surface and interface morphology, and magnetic and electrical properties. When three different structures of multilayered thin film were compared, magnetization of CNF/BTO/CNF thin films was decreased by magnetic and dielectric interaction. Also we confirmed that capacitance of CNF/BTO/CNF multilayered thin film was enhanced as being near tetragonal structure with increasing of c/a ratio because of atomic bonding at interface between BTO dielectric and CNF magnetic materials. Finally, we studied the change of the capacitance of CNF/BTO/CNF multilayered thin film with magnetic field for emergence of magnetocapacitance and suggested a possibility of enhanced capacitance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.3-6
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• 2003

This paper describes the interface stability of Ta-Mo alloy metal on $SiO_2$ Alloy was formed by co-sputtering method, and the alloy composition was varied by controlling Ta and Mo sputtering power. When the atomic composition of Ta was about 91%, the measured work function was 4.2eV that is suitable for NMOS gate. To identify interface stability between Ta-Mo alloy metal and $SiO_2$, C-V, FE-SEM(Field Emission-SEM), and XRD(X-ray diffraction) were performed on the samples annealed with rapid thermal processor between $600^{\circ}C$ and $900^{\circ}C$. Even after $900^{\circ}C$ rapid thermal annealing, excellent interface stability and electrical properties were observed. Also, thermodynamic analysis was studied to compare with experimental results.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.226-231
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• 2001

The effect of interface reaction between Mn-Zn ferrite single crystal and 61 SiO$_2$-23Pbo-6ZnO-8Na$_2$O-2K$_2$O (mol%) glass on the magnetic properties of the ferrite was investigated. After the reaction, the hump of Zn concentration appeared at the ferrite adjacent to the interface. The initial permeability of the ferrite bonded with the glass at 700 $^{\circ}C$ was 1766 at 100 KHz and reduced to 907 after reaction at 1000$^{\circ}C$. The permeability degradation with increasing reaction temperature was considered to be attributed not only to the sixe diminution of the ferrite due to the its dissolution into the glass but also to the residual stress due to the difference in expansion coefficient between the ferrite and the diffusion layer-the region of the hump of Zn concentration-adjacent to the interface.

• Journal of the Korean Ceramic Society
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• v.30 no.6
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• pp.510-516
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• 1993

$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$\AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{\circ}C$ to $900^{\circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{\circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.29-34
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• 1992

Phase transition, dielectric properties, and leakage current characteristics of Ta2O5 thin film fabricated by sol-gel process with tantalum penta-n-butoxide were studied as a function of annealing temperature in O2 atmoshpere. Although Ta2O5 thin film annealed at temperatures below 700$^{\circ}C$ for 1 hr was amorphous, it was crystallized to ${\beta}$-Ta2O5 of orthorhombic phase by annealing at temperatures higher than 750$^{\circ}C$. With increasing annealing temperature from 500$^{\circ}C$ to 900$^{\circ}C$, dielectric constant of sol-gel processed Ta2O5 thin film was changed from 17.6 to 15.3 due to the increase of SiO2 thickness at Ta2O5/Si interface. For Ta2O5 thin film annealed at 500$^{\circ}C$ to 800$^{\circ}C$ for 1 hr in O2 atmosphere, leakage current was remarkably reduced and breakdown strength was increased with higher annealing temperature. For Ta2O5 film annealed at 800$^{\circ}C$, breakdown did not occur even at electric field strength of 30${\times}$105V/cm and leakage current was maintained lower than 10-8A/$\textrm{cm}^2$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.1
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• pp.34-41
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• 2017

In this study, the effect on the zinc nuclei crystallization caused by changes preprocessing of the zinc crystalline glaze preparation has been studied. The mechanism of the nuclei formation in the crystalline glaze and development of the nuclei by studying the preprocessing step was explained. The preprocessing step was improved by altering mixing process of the materials prior to sintering: number of sieving dispersion process and ultra-sonication prove tests with various duration of sonication. According to the result, the sieving and sonication of the starting materials facilitated the interface reactions of $ZnO-SiO_2$ from $680^{\circ}C$ where low temperature willemite is formulated, and altered Si bonding for the easier bonding between Zn-Si. In other words, solely sieving was enough to accelerate the formation of willemite in low temperature. When the particles were distributed evenly by sonication, the willemite formation was even more significant.

• Korean Journal of Metals and Materials
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• v.50 no.4
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• pp.300-309
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• 2012

Low-carbon steels and a stainless steel were oxidized isothermally and cyclically between $1050^{\circ}C$ and $1200^{\circ}C$ for up to 100 min in air to find the effect of alloying elements of Si, Mn, Ni, and Cr on their oxidation. The most active alloying element of Si was scattered inside the oxide scale, at the scale-alloy interface and as internal oxide precipitates beneath the oxide scale. Manganese, which could not effectively improve the oxidation resistance, was rather uniformly distributed in the oxide scale. Nickel and chromium tended to present at the lower part of the oxide scale. Excessively thick porous scales formed on the low-carbon steels, whereas thin but non-adherent scales containing $Cr_2O_3$ formed on the stainless steel.