• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제14권5호
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• pp.423-429
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• 2001

PbS, CuS and (Pb,Cu)S thin films were chemically deposited on glass from alkaline baths containing lead acetate, copper chloride, thiourea and triethanolamine. The deposition, optical, resistivity and thermal electric properties of these films were studied. PbS thin films showed a hexagonal structure and CuS thin films showed amorphous. The crystalline of (Pb,Cu)S thin films was obtained by heat treatment at 200$\^{C}$ and the deposition ratio of Pb to Cu showed 7:3. The energy gap of PbS, CuS and (Pb,Cu)S thin films were 1.7, 2.1 and 2.4 eV, respectively. Sheet resistance of PbS thin films was less affected on thermal annealing, but hose of (Pb,Cu)S and CuS thin films were more reduced about 3 orders of magnitude. All of those thin films indicated p type semiconductor in temperature ranging 30$\^{C}$ to 150$\^{C}$.

• Transactions on Electrical and Electronic Materials
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• 제10권5호
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• pp.165-168
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• 2009

Transparent and conducting ITO/Cu/ITO multilayered films were deposited by magnetron sputtering on unheated polycarbonate (PC) substrates. The thickness of the Cu intermediate film was varied from 5 to 20 nm. Changes in the microstructure and optoelectrical properties of ITO/Cu/ITO films were investigated with respect to the thickness of the Cu intermediated layer. The optoelectrical properties of the films were significantly influenced by the thickness of the Cu interlayer. The sandwich structure of ITO 50 nm/Cu 5 nm/ITO 45 nm films had a sheet resistance of $36{\Omega}$/Sq. and an optical transmittance of 67% (contain substrate) at a wavelength of 550 nm, while the ITO 50 nm/Cu 20 nm/ITO 30 nm films had a sheet resistance of $70{\Omega}$/Sq. and an optical transmittance of 36%. The electrical and optical properties of ITO/Cu/ITO films were determined mainly by the Cu film properties. From the figure of merit, it is concluded that the ITO/Cu/ITO films with a 5 nm Cu interlayer showed the better performance in transparent conducting electrode applications than the conventional ITO films.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.178.2-178.2
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• 2015

In and Ga doped ZnO (IGZO) films were deposited on 5 nm thick Cu film buffered Polycarbonate (PC) substrates with RF magnetron sputtering and then the effect of Cu buffer layer on the optical and electrical properties of the films was investigated. While IGZO single layer films show the electrical resistivity of $1.2{\times}10-1{\Omega}cm$, IGZO/Cu bi-layered films show a lower resistivity of $1.6{\times}10-3{\Omega}cm$. Although the optical transmittance of the films in a visible wave length range is deteriorated by Cu buffer layer, IGZO films with 5 nm thick Cu buffer layer show the higher figure of merit of $2.6{\times}10-4{\Omega}-1$ than that of the IGZO single layer films due to the enhanced opto-electrical performance of the IGZO/Cu bi-layered films.

• Journal of the Korean Institute of Telematics and Electronics D
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• 제36D권3호
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• pp.59-65
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• 1999

In this paper, we had studied the possibility of application as Cu thin films from (hfac)Cu(VTMOS) which is very stable. Cu thin films had been studied as a function of deposition temperature. Substrates used in the experiment were PVD TiN on Si wafer. Deposition conditions were as follow : deposition temperature $50^{\circ}C$. Cu thin films were analyzed by AES, four point probe, XRD and SEM. All of deposited films were very pure and some favoring of <111> planes perpendicular to the substrate surface were observed. Cu thin films had two distinct growth rates at various deposition temperature. One is the surface reaction limited region below $200^{\circ}C$, and the other is the mass transport limited region above $200^{\circ}C$. The resistivity of deposited Cu thin films under the optimum deposition condition is $2.5mu\Omega.cm$ Thus, properties of deposited Cu thin films using (hfac)Cu(VTMOS) didn't show difference with Cu thin films from other precursors.

• Korean Journal of Metals and Materials
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• 제48권10호
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• pp.884-892
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• 2010

To modify the physical properties of Cu thin films, gelatin is generally used as an additive. In this study, we assessed the effect of gelatin on the mechanical properties of electrodeposited Cu films. For this purpose, Cu/gelatin composite films were fabricated by adding 100 ppm of gelatin to an electrolyte, and tension and indentation tests were then performed. Additional tests based on pure Cu films were also performed for comparison. The Cu films containing gelatin presented a smaller grain size compared to that of pure Cu films. This increased the hardness of the Cu films, but addition of gelatin did not significantly affect the elastic modulus of the films. Cu films prepared at room temperature showed no significant change in the yield strength and tensile strength with an addition of gelatin, but we observed a dramatic decrease in the elongation. In contrast, Cu films prepared at $40^{\circ}C$ with gelatin presented a significant increase in the yield strength and tensile strength after the addition of gelatin. Elongation was not affected by adding gelatin. Presumably, the results would be closely related to the preferred orientation of the Cu thin film with the addition of gelatin and at temperatures that lead to a change in the microstructure of the Cu thin films.

• Korean Journal of Materials Research
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• 제16권4호
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• pp.257-263
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• 2006

We have investigated the effect of silver added to Cu films on the microstructure evolution, resistivity, surface morphology, stress relaxation temperature, and adhesion properties of Cu(Ag) alloy thin films deposited on Mo glue layer upon annealing. In addition, pure Cu films deposited on Mo has been annealed and compared. The results show that the silver in Cu(Ag) thin films control the grain growth through the coarsening of its precipitates upon annealing at $300^{\circ}C{\sim}600^{\circ}C$ and the grain growth of Cu reveals the activation energy of 0.22 eV, approximately one third of activation energy for diffusion of Ag dopant along the grain boundaries in Cu matrix (0.75 eV). This indicates that the grain growth can be controlled by Ag diffusion along the grain boundaries. In addition, the grain growth can be a major contributor to the decreased resistivity of Cu(Ag) alloy thin films at the temperature of $300^{\circ}C{\sim}500^{\circ}C$, and decreases the resistivity of Cu(Ag) thin films to $1.96{\mu}{\Omega}-cm$ after annealing at $600^{\circ}C$. Furthermore, the addition of Ag increases the stress relaxation temperature of Cu(Ag) thin films, and thus leading to the enhanced resistance to the void formation, which starts at $300^{\circ}C$ in the pure Cu thin films. Moreover, Cu(Ag) thin films shows the increased adhesion properties, possibly resulting from the Ag segregating to the interface. Consequently, the Cu(Ag) thin films can be used as a metallization of advanced TFT-LCDs.

• Journal of the Korean institute of surface engineering
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• 제27권5호
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• pp.261-272
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• 1994

Both Cu-Cr and Cu-Ti alloy films with different composition were prepared by dc magnetron sputtering onto polyimide substrate and their adhesion and microstructure were observed. In addition, the effect of heat treatment at $400^{\circ}C$ for 2 hours on the variation of adhesion properties and on the changess of microstructure were investigated. Cu-Cr alloy films have crystalline structure of either for or bcc phase depending on the composition of the film. However, the Cu-Ti alloy film forms fcc phase at low Ti concentration while it forms an amorphous phase as the Ti concentration in the films is increased to more than 25at.%. TEM analysis reveal that the microstructure of Cu-Cr and Cu-Ti films forms an open structure with vacant spaces. The adhesion between Cu-Cr, Cu-Ti alloy films and polyimide substrate is relatively good before the heat treatment, but is noticeably reduced after the heat treatment. In particular, the adhesion strength is significantly reduced in the Cu-Ti alloy films after the heat treatment. The reduction of adhesion strength after the heat treatment is identified to relate with the formation of oxide phases at the metal/polyimide interface by AES(Auger Electron Spectroscopy).

• Electrical & Electronic Materials
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• 제8권3호
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• pp.298-305
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• 1995

Copper-indium diselenide, $CuInSe_2$, thin films have been fabricated by selenizing Cu/In stacked layers with different sputtered Cu/(Cu+ln) mole ratios at 450.deg. C for 1hr on alumina substrates. The selenium source was selenium vapor. Microstructure, crystallization, and composition of the selenized $CuInSe_2$ films were examined by using scanning electron microscope, X-ray diffraction, Auger electron spectroscopy, and secondary ion mass spectrometry. Electrical resistivity and hall effects were also measured to investigate the electrical properties. As the sputtered Cu/(Cu+In) mole ratio of In/Cu layer increased, the amounts of void and CuSe phase in the selenized films increased but the composition of $CuInSe_2$ phase was the same regardless of the sputtered mole ratio. Comparing the electrical properties of $CuInSe_2$ thin film before and after the chemical etching, it was seen that the electrical resistivity, carrier concentration, and carrier mobility of the selenized films were affected by the amount of CuSe phase which seemed to increase primarily the hole concentration of the selenized films.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.175.1-175.1
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• 2015

CuSn thin films were deposited by rf magnetron co-sputtering method with pure Cu and Sn metal targets with a variety of rf powers. CuSn thin films were studied with a surface profiler (alpha step), X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), X-ray diffraction (XRD), and contact angle measurement. The thickness of CuSn thin films was fixed at $200{\pm}10nm$ and deposition rate was calculated by the measured with a surface profiler. From the survey XPS spectra, the characteristic peaks of Cu and Sn were observed. Therefore, CuSn thin films were successfully synthesized on the Si (100) substrate. The oxidation state and chemical environment of Cu and Sn were investigated with the binding energy regions of Cu 2p XPS spectra, Sn 3d XPS spectra, and Cu LMM Auger spectra. Change of the crystallinity of the films was observed with XRD spectra. Using contact angle measurement, surface free energy (SFE) and wettability of the CuSn thin films were studied with distilled water (DW) and ethylene glycol (EG).