• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.272.2-272.2
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• 2016

Copper-Tin (CuSn) thin films were synthsized by rf magnetron co-sputtering method with pure Cu and Sn metal targets with various rf powers and sputtering times. The obtained CuSn thin films were characterized by a surface profiler (alpha step), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), and contact angle measurement. The deposition rates were calculated by the thickness of CuSn thin films and sputtering times. We observed hexagonal Cu20Sn6 and cubic Cu39Sn11 phases from the films by XRD measurement. From the survey XPS spectra, the Cu and Sn main peaks were observed. Therefore, we could conclude CuSn thin films were successfully fabricated on the substrate in this study. The changes of oxidation states and chemical environment of the films were investigated with high resolution XPS spectra in the regions of Cu 2p, Cu LMM, and Sn 3d. Surface free energy (SFE) and wettability of the CuSn thin films were studied with distilled water (DW) and ethylene glycol (EG) using the contact angle measurement. The total SFE of CuSn thin films decreased as rf power on Cu target increased. The contribution to the total SFE of dispersive SFE was relatively superior to polar SFE.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.481-489
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• 1994

The $SnO_2$/(n)Si solar cell was fabricated by electron beam evaporation method, and their properties were investigated. In proportion to increase of substrate and annealing temperature, the conductivity of $SnO_2$ thin film was increased, but its optical transmission decreases because of increasing optical absorption of free electrons in the thin film. $SnO_2$/Si Solar cell characteristics were improved by annealing, but the solar cells was deteriorated by heat treatment above 500[.deg. C]. The optimal outputs of $SnO_2$/Si solar cell through above investigations were $V_{\var}$:350[mV], $J_{sc}$ ;16.53[mA/c $m^{2}$], FF;0.41, .eta.=4.74[%]

• Journal of the Korean institute of surface engineering
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• v.28 no.2
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• pp.67-76
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• 1995

The microstructure of 95wt.%Pb/5wt.%Sn and 63wt.%Sn/37wt.%Pb solders for flip chip bonding process has been characterized. Solders were deposited by thermal evaporation and reflowed in the conventional furnace or by rapid thermal annealing(RTA) process. As-deposited films show columnar structure. The microstructure of furnace cooled 63Sn/37Pb solder shows typical lamellar form, but that of RTA treated solder has the structure showing an uniform dispersion of Pb-rich phase in Sn matrix. The grain size of 95Pb/5Sn solder reflowed in the furnace is about $5\mu\textrm{m}$, but the grain size of RTA treated solder is too small to be observed. The microstructure in 63Sn/37Pb solder bump shows the segregation of Pb phase in the Sn rich matrix regardless of reflowing method. The 63Sn/37Pb solder bump formed by RTA process shows more uniform microstructure. These result are related to the heat dissipation in the solder bump.

• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.486-490
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• 1993

Cd4SnSea6 & Cd4SnSe6 : Co2+ single crystals were grown by the chemical transport reaction (CTR) method. The grown single crystlas crrystallize in the monoclinic structrue and have the direct band gaps. The energy gaps of them are 1.68eV for Cd4SnSea6 & Cd4SnSe6 : Co2+ at 293K. The impurity opticla absorption peaks due to cobalt dped with impurity appear at 4879cm-1, 5392cm-1 and 6247 com-1, and are attributed to the electron transitions between the split energy levels of Co2+ ion sited at Td symmetry of Cd4SnSe6 single crystal.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1207-1208
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• 2006

We developed the copper core ball electroplated with Sn-Ag-Cu of the eutectic composition which used mostly as Pb free solder ball with high reliability. In order to search for the practicality of this developed copper core ball, the evaluation was executed by measuring the initial joint strength of the sample mounted on the substrate and reflowed and by measuring the joint strength of the sample after the high temperature leaving test and the constant temperature and the humidity leaving test. This evaluation was compered with those of the usual other copper core balls electroplated with (Sn,Sn-Ag,Sn-Cu,Sn-Bi) and the Sn-Ag-Cu solder ball.

• Electrical & Electronic Materials
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• v.9 no.1
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• pp.38-43
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• 1996

A coprecipitation method was used for preparing Ca and Pt doped $SnO_2$ fine powder. Components of the powder were investigated by XPS and SIMS. Crystallite size and specific surface area were investigated by TEM, XRD, and BET analysis. $SnO_2$(Ca)/Pt based thick film devices were prepared by a screen printing technique for methane gas detection. Then sensing characteristics of the devices were investigated. As Ca and Pt added, the crystal growth of $SnO_2$ was suppressed during calcining and sintering, and the sensitivity of $SnO_2$(Ca)/Pt thick film to methane gas was enhanced. For the Pt doped $SnO_2$ fine particle, the thick film device shows sensitivity of about 83% to 2000 ppm methane gas at an operating temperature of >$400^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.680-686
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• 2006

Tin oxide$(SnO_2)$ thin films were prepared on glass substrate by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. $SnO_2$ thin films were prepared using gas mixture of dibutyltin diacetate as a precursor and oxygen as an oxidant at 275, 325, 375, $425^{\circ}C$, respectively as a function of deposition temperature. The XRD peaks corresponded to those of polycrystalline $SnO_2$, which is in the tetragonal system with a rutil-type structure. As the deposition temperature increased, the texture plane of $SnO_2$ changed from (200) plane to denser (211) and (110) planes. Lower deposition temperature and shorter deposition time led to decreasing surface roughness and electrical resistivity of the formed thin films at $325\sim425^{\circ}C$. The properties of $SnO_2$ films were critically affected by deposition temperature and time.

• Journal of the Korean Chemical Society
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• v.27 no.6
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• pp.424-482
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• 1983

Determination for $Ta_2O_5$,$Nb_2O_5$ and $SnO_2$ in tin slags was investigated by X-ray spectrometric method. Standard addition-dilution method was attempted and showed a comparable accuracy with standard calibration curve method. Pure chemicals($Ta_2O_5$,$Nb_2O_5$ and $SnO_2$) were added to the samples and diluted with silica or ferric oxide. For the determination of $Ta_2O_5$and$SnO_2$ , silica was more suitable than ferric oxide while the latter was more preferable than the former for $Nb_2O_5$.

• Journal of the Korean Ceramic Society
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• v.54 no.3
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• pp.243-248
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• 2017

Pd-doped $SnO_2$ thick film with a pure tetragonal phase was prepared on patterned Pt electrodes by an ink dropping method. Nanostructured $SnO_2$ powder with a diameter of 10 nm was obtained by a modified hydrazine method. Then the ink solution was fabricated by mixing water, glycerol, bicine and the Pd-doped $SnO_2$ powder. When the Pd doping concentration was increased, the grain size of the Pd-doped $SnO_2$ thick film became smaller. However, an agglomerated and extruded surface morphology was observed for the films with Pd addition over 4 wt%. The orthorhombic phase disappeared even at a low Pd doping concentration and a PdO peak was obtained for a high Pd doping concentration. The crack-free Pd-doped $SnO_2$ thick films were able to successfully fill the $30{\mu}m$ gap of the patterned Pt electrodes by the optimized ink dropping method. The prepared 3 wt% Pd-doped $SnO_2$ thick films showed monoxide gas responses ($R_{air}/R_{CO}$) of 4.0 and 35.6 for 100 and 5000 ppm, respectively.

• Journal of information and communication convergence engineering
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• v.7 no.1
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• pp.72-77
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• 2009

Three different procedures for adding Pd compounds to $SnO_2$ particles have been investigated. These processes are: (1) coprecipitation; (2) dried powder impregnation; and (3) calcined powder impregnation. The microstructures of $SnO_2$ particles have been analyzed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). In the coprecipitaion method, the process does not restrain the growth of $SnO_2$ particles and it forms huge agglomerates. In the dried powder impregnation method, the process restrains the growth of $SnO_2$ particles and the surfaces of the agglomerates have many minute pores. In the calcined powder impregnation method, the process restrains the growth of $SnO_2$ particles further and the agglomerates have a lot more minute pores. The sensitivity ($S=R_{air}/R_{gas}$) of the $SnO_2$ gas sensor made by the calcined powder impregnation process shows the highest value (S = 21.5 at 5350 ppm of $C_3H_8$) and the sensor also indicates the lowest operating temperature of around $410^{\circ}C$. It is believed that the best result is caused by the plenty of minute pores at the surface of the microstructure and by the catalyst Pd that is dispersed at the surface rather than the inside of the agglomerate. Schematic models of Pd distribution in and on the three different $SnO_2$ particles are presented.