• Journal of dental hygiene science
• /
• v.9 no.4
• /
• pp.405-412
• /
• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Journal of the Microelectronics and Packaging Society
• /
• v.28 no.2
• /
• pp.29-37
• /
• 2021

The effect of Ar/N₂ two-step plasma treatment on the quantitative interfacial adhesion energy of low temperature Cu-Cu bonding interface were systematically investigated. X-ray photoelectron spectroscopy analysis showed that Ar/N₂ 2-step plasma treatment has less copper oxide due to the formation of an effective Cu4N passivation layer. Quantitative measurements of interfacial adhesion energy of Cu-Cu bonding interface with Ar/N₂ 2-step plasma treatment were performed using a double cantilever beam (DCB) and 4-point bending (4-PB) test, where the measured values were 1.63±0.24 J/m² and 2.33±0.67 J/m², respectively. This can be explained by the increased interfacial adhesion energy according phase angle due to the effect of the higher interface roughness of 4-PB test than that of DCB test.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.11a
• /
• pp.28.2-28.2
• /
• 2009

Cobalt thin film was fabricated by a novel NH3-based plasma-enhanced atomic layer deposition(PE-ALD) using Co(CpAMD) precursor and $NH_3$ plasma. The PE-ALD Co thin films were produced well on both thermally grown oxide (100 nm) $SiO_2$ and Si(001) substrates. Chemical bonding states and compositions of PE-ALD Co films were analyzed by XPS and discussed in terms of resistivity and impurity level. Especially, we successfully developed PE-ALD Code position at very low growth temperature condition as low as $T_s=100^{\circ}C$, which enabled the fabrication of Co patterns through lift-off method after the deposition on PR patterned substrate without any thermal degradation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.05a
• /
• pp.227-229
• /
• 1995

Using thermal oxide SiO$_2$ as a dielectrical isolation layer, SOI Hall sensors without pn junction isolation have been fabricated on Si/SiO$_2$/Si structures. The SOI structure was formed by SDB (Si- wafer direct bonding) technology. The Hall voltage and the sensitivity of Si Hall devices implemented on the SDB SOI structure show good linearity with respect to the appled magnetic flux density and supplied current. The product sensitivity of the SDB SOI Hall device is average 600V/V.T. In the trmperature range of 25 to 300$^{\circ}C$, the shifts of TCO(Temperature Coefficient of the Offset Voltage) and TCS(Temperature Coefficient of the Product Sensitivity) are less than ${\pm}$ 6.7x10$\^$-3/ C and ${\pm}$8.2x10$\^$04/$^{\circ}C$, respectively. These results indicate that the SDB SOI structure has potential for the development of Hall sensors with a high-sensitivity and high-temperature operation.

• Journal of the Korean Vacuum Society
• /
• v.8 no.2
• /
• pp.136-140
• /
• 1999

The stability and response time of $WO_3$ thin films for EC device are critical problems being solved. Those are affected by the species of electrolyte, preparation conditions and fabricating methods of specimen. In this paper, we compared the stabilities of three kinds of tungsten oxide film in electrolyte. Each of three films was prepared by different manufacturing conditions, that is, one is a thermal oxidation film of tungsten metal deposited on pure glass substrate, another is a $WO_3$ film made on ITO glass directly, the other is a thermally oxidized film on tungsten plate. It was observed that thermally oxidized $WO_3$ films has a remarkable stability (the lifetime was above $10^6$ cycle). From these results, we found that the stability was closely related to the stoichiometric bonding between tungsten and oxygen atoms in addition to crystallinity and density of film.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.220-220
• /
• 2003

최근, Cu기판 위에 YBaCuO$_{7-x}$ 초전도체를 입혀 초전도 선재를 제작하려는 연구가 이루어지고 있으며 이 과정에서 CuO와 Cu$_2$O가 생성된다는 보고가 있다. CuO 및 Cu$_2$O의 생성은 초전도 선재의 전기전도적 특성 및 기계적 특성에 상당한 영향을 끼칠 수 있다. 따라서 CuO와 Cu$_2$O에 대한 연구가 필요하다고 할 수 있다. 본 연구에서는 DV-X$\alpha$ 분자궤도법을 통해 CuO와 Cu$_2$O에 대한 (Cu$_{29}$ O$_{58}$ )$^{58-}$ , (Cu$_{52}$ O$_{19}$ )$^{14+}$ 모델을 이용하여 전자상태계산을 하였다. CuO, Cu$_2$O의 valence orbital level 구조 및 DOS (Density of State)를 통해 Cu원자와 O원자간의 공유결합 세기를 측정하였으며 CuO, Cu$_2$O 서로간의 차이점을 분석하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.12
• /
• pp.977-982
• /
• 2000

Conventional transistors which have vertical structure show increased parasitic capacitance characteristics in accordance with the increase of non-active base area and collector area. These consequently have disadvantage for high speed switching performance. In this paper, a lateral structure transistor which has minimized parasitic capacitance by using SDB(Silicon Direct Bonding) wafer and oxide sidewall isolation utilizing silicon trench technology is presented. Its structural characteristics are designed by ATHENA(SUPREM4), the process simulator from SILVACO International, and its performance is proven by ATLAS, the device simulator from SILVACO International. The performance of the proposed lateral structure transistor is certified through the V$\_$CE/-I$\_$C/ characteristics curve, h$\_$FE/-I$\_$C/ characteristics, and GP-plot. Cutoff Frequency is 13.7㎓.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.295-295
• /
• 2006

In present study, poly(acrylic acid) (PAA) and hydrophobically modified poly(ethylene oxide) (HM-PEO) multilayers based on the hydrogen bonding between the component polymer pair have been prepared by the LbL deposition method. Dip assembled HM-PEO/PAA multilayers yield unique film morphologies in comparison with PEO/PAA multilayers due to the micellar formation of HM-PEO owing to the hydrophobic attraction between alkyl chains end-capped with the PEO chains. Individual HM-PEO micelles were connected through the bridging PEO chains to form temporary networks on multilayer surface and induced peculiar surface morphology on HM-PEO/PAA multilayers above the critical number of bilayers.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.12
• /
• pp.2369-2376
• /
• 2007

N2O has been found from experimental and theoretical considerations to bind on-top to the Pd(110) surface in a tilted end-on fashion via its terminal N atom. We use a frontier orbital description of the bonding interactions in the Pd-N2O system to obtain molecular insight into the catalytic mechanism of the activation of N2O by the Pd(110) surface giving rise to the formation of N2 and O on the surface. For the tilted end-on N2O binding mode, the LUMO 3π of N2O has good overlap with the Pd dσ and dπ orbitals which can serve as the electron donors. The donor-acceptor orbital overlap is favorable for electron transfer from Pd to N2O and is expected to dominate the surface reaction pathway of N2O decomposition.

• Journal of the Korean Ceramic Society
• /
• v.31 no.12
• /
• pp.1443-1448
• /
• 1994

Pb(Mg1/3Nb2/3)O3-PbTiO3-BaTiO3 solid solution was formed by mixed-oxide method. The phase during formation was analysed by XRD and formation mechanism was investigated. While heat-treating Pb(Mg1/3Nb2/3)O3 composition, the first, Pb2Nb2O7 and Pb3Nb2O8 pyrochlore phases are formed, and finally Pb(Mg1/3Nb2/3)O3 perovskite phase with containing Pb3Nb4O13 pyrochlore phase is obtained at 80$0^{\circ}C$. When Pb(Mg1/3Nb2/3)O3 composition is modified with PbTiO3 which have strong ionic bonding and high tolerance factor, the amount of pyrochlore phase is decreased by increasing of stability in perovskite structure.