• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1542-1545
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• 2005

Transparent conducting aluminum-doped zinc oxide (AZO) thin films have been deposited on corning 1737 glass by DC magnetron sputter. The structural, electrical and optical properties of the films were investigated as a function of various substrate temperatures. AZO thin films were fabricated by dc magnetron sputtering with AZO ceramic target $(Al_2O_3: 2wt %)$. The obtained films were poly crystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The lowest resistivity is $6.0{\times}10^{-4}$ Ocm with the carrier concentration of $2.694{\times}10^{20}\;cm^{-3}$ and Hall mobility of $20.426cm^2/Vs$. The average transmittance in the visible range was above 90%.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1145-1146
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• 2015

In this study, HAZO thin films were deposited on glass substrates at room temperature via co-sputtering with RF magnetron sputter. The effects of additive oxygen gas in sputtering on the structural and optical characteristics of HAZO thin films were investigated using X-ray diffraction and UV/Vis spectrometer. The experimental results confirmed that the hafnium oxides formed in the HAZO films when they were deposited with oxygen gas, which affected on the structure and transmittance of the films.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.202-202
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• 2010

불순물이 첨가되는 이원계 및 다원계 투명전도성 산화막들은 불순물의 첨가량에 따라서 전기적 그리고 광학적 특성의 변화를 나타낸다. 조성비에 따른 특성 변화를 조사하기 위하여 산화아연 타겟과 산화갈륨 타겟을 이용하여 혼합 스퍼터링 방식을 이용하여 인듐, 갈륨 등이 소량 첨가된 산화아연막(IGZO)을 증착하였다. Triple Co-sputter의 인가 전력을 변화시켜 가면서 박막 구성 원소들의 성분비 변화에 따른 전기적 그리고 광학적 특성을 조사하였다. 증착된 박막들은 조성비에 따라 전기적 그리고 광학적 특성이 변화되는 것을 확인하였다. 실온에서 유리기판 위에 증착된 박막은 저항률이 $2^*10^{-3}\;{\Omega}-cm$의 전기적 특성을 보였고, 투과도가 400~800nm 파장 범위 내에서 80% 이상의 광학적 특성을 보였다.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.263-271
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• 1994

We have produced $Co_{1-x}Pt_{x}(X\;=\;0.53\;and\;0.75)$ alloy films by DC magnetron sputtering at various substrate temperatures and sputtering pressures. Sputter-deposited Co-Pt alloy films showed a strong (111) texture, and the degree of (111) texture of the as-deposited film was found to depend on the substrate temperature and Ar pressure. However, we observed that the degree of (111) texture did not affect the magnetic properties. In addition, we have investigated the effect of heat-treatment on magnetic properties of these films. While the magnetic properties of the $Co_{0.25}Pt_{0.75}$ alloy films showed no noticeable changes, the coercivities and the squarenesses of the $Co_{0.47}Pt_{0.53}$ alloy films were drastically increased by annealing. Structural analysis using transmission electron microscopy(TEM) and x-ray diffractornetry(XRD) revealed that $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases, respectively, were formed, each with a strong (111) texture. By comparing the magnetic properties between $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases in relation to the atomic arrangements in a unit cell, we conclude that the magnetic anisotropy in the Co-Pt alloy system depends mainly on the atomic arrangements of Co and Pt.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.184-188
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• 2001

Using a DC-sputter and changing the substrate temperature to room temperature and 200$\^{C}$, we manufactured each Co-22%Cr alloy thin-films, which has a uniform micro-structure at room temperature, and a fine self-organized nato structure (SONS) at the inside of the grain at the elevated temperature. We also investigated the microstructure and domain structure using a transmission electron microscope (TEM) and a magnetic force microscope (MFM). We managed to corrode selectively Co-enriched phase, then investigate the microstructure using a TEM. We found that it has a uniform composition when it is manufactured at room temperature, but, we found that it has a unique microstructure, which has a plate-like fine Co-enriched phase, with the formation of SONS at the inside of the grain at the elevated temperature. In MFM characterization, we found maze-type domains at the period of 5000 when the substrate temperature maintains at room temperature. We define that the maze-type domain has a disadvantage at the high density recording because it generates noises easily as the exchange coupling energy between the grains is big. On the other hand, there is only a fine domain structure at the period of 500 when the substrate temperature maintains at 200 $\^{C}$. We define that the fine domain structure has an advantage at the high density magnetic recording because it has thermal stability due to small exchange coupling energy.

• Journal of Powder Materials
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• v.23 no.1
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• pp.21-25
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• 2016

The microstructural properties and electrical characteristics of sputtering films deposited with a Cu-Ga target are analyzed. The Cu-Ga target is prepared using the cold spray process and shows generally uniform composition distributions, as suggested by secondary ion mass spectrometer (SIMS) data. Characteristics of the sputtered Cu-Ga films are investigated at three positions (top, center and bottom) of the Cu-Ga target by X-ray diffraction (XRD), SIMS, 4-point probe and transmission electron microscopy (TEM) analysis methods. The results show that the Cu-Ga films are composed of hexagonal and unknown phases, and they have similar distributions of composition and resistivity at the top, center, and bottom regions of the Cu-Ga target. It demonstrates that these films have uniform properties regardless of the position on the Cu-Ga target. In conclusion, the cold spray process is expected to be a useful method for preparing sputter targets.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.211-216
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• 2003

In this paper, characteristics of Ta-Ti alloy was studied as a gate electrode for NMOS devices to replace the widely used polysilicon. Ta-Ti alloy was deposited directly on $SiO_2$ by a co-sputtering method using two of Ta and Ti targets. The sputtering power of each metal target was 100W. To compare with Ta-Ti, Ta deposited with a 100W sputtering power was fabricated as well. In order to investigate the thermal/chemical stability of the Ta-Ti alloy gate, the alloy was annealed at $600^{\circ}C$ with rapid thermal annealer. No appreciable degradation of the device was observed. Also the results of electrical analysis showed that the work function of Ta-Ti metal alloy was about 4.1eV which was suitable for NMOS devices and sheet resistance of alloy was lower than that of polysilicon.

• Progress in Superconductivity
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• v.5 no.2
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• pp.105-108
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• 2004

We have studied effects of in-situ annealing on the fabrication of superconducting MgB$_2$ thin films prepared by rf magnetron co-sputtering. The Films were deposited on A1$_2$O$_3$ (1102) substrates at room temperature by using Mg and B targets. To trap remnant $O_2$ gas in the chamber, we used 20 mtorr Af sputter-gas balanced with 5 mol % of H$_2$ gas. To enhance adhesion to the substrate a thin layer of B was deposited prior to the codeposition of Mg and B. After completion of the film deposition, an additional Mg layer was deposited on top to compensate for Mg loss during the subsequent in-situ annealing. We have investigated the effects of two most important annealing parameters that are the Mg-to-B composition ratio and the annealing temperature. The range of the Mg-to-B composition ratio was from 0.42 to 0.85, and that of the annealing temperature was 500 $^{\circ}C$∼750 $^{\circ}C$. The Best result was obtained for the composition ratio of about 10% Mg excess from the stoichiometry and the annealing temperature of 700 $^{\circ}C$. Based on these results, we obtained films with T$_{c}$ : 36.5 K by further refining the fabrication process.s.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.382-382
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• 2012

CIGS thin films have received great attention as a promising material for solar cells due to their high absorption coefficient, appropriate bandgap, long-term stability, and low cost production. CIGS thin films are deposited by various methods such as co-evaporation, sputtering, spray pyrolysis and electro-deposition. The deposition technique is one of the most important processes in preparing CIGS thin film solar cells. Among these methods, co-evaporation is one of the best technique for obtaining high quality and stoichiometric CIGS films. However, co-evaporation method is known to be unsuitable for commercialization. The sputtering is known to be very effective and feasible process for mass production. In this study, CIGS thin films have prepared by rf magnetron sputtering using a $Cu(In_{1-x}Ga_x)Se_2$ single quaternary target without post deposition selenization. This process has been examined by the effects of deposition parameters on the structural and compositional properties of the films. In addition, we will explore the influences of substrate temperature and additional annealing treatment after deposition on the characteristics of CIGS thin films. The thickness of CIGS films will be measured by Tencor-P1 profiler. The crystalline properties and surface morphology of the films will be analyzed using X-ray diffraction and scanning electron microscopy, respectively. The optical properties of the films will be determined by UV-Visible spectroscopy. Electrical properties of the films will be measured using van der Pauw geometry and Hall effect measurement at room temperature using indium ohmic contacts.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.404-405
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• 2011

Cu(InGa)$Se_2$ (CIGS) 박막 태양전지의 저가 및 대면적화를 위한 양산화 공정인 two-step process (sputter/selenization) 공정에서는 sputtering으로 형성한 metal precursor stack을 $H_2$ Se gas를 이용하여 selenization하는 공정을 주로 이용한다. 하지만 이러한 selenization 공정은 유독한 $H_2$ Se gas를 이용해야 한다는 점과 긴 시간 동안 열처리를 해야 하는 단점을 가지고 있다. 이에 metal precursor stack 위에 Se 막을 우선 증착하고, Rapid Thermal Process (RTP)를 이용하여 selenization하는 방법이 현재 많은 관심을 끌고 있다. 본 논문에서는 sputtering 이후 RTP를 이용한 CIGS 흡수층 제작에 대한 선행연구의 일환으로 co-evaporator 장비를 이용하여 다양한 구조의 precursor를 제작하고 RTP 조건에 따른 selenization 효과를 연구하였다. Co-evaporator를 이용하여 CIGS, CIG/Se, CuGa/In/Se, In/CuGa/Se 4가지 구조의 precursor stack을 Mo coated soda lime glass 위에 제작하였다. 이때 amorphous 상태의 precursor stack을 만들기 위하여 기판에 열은 가하여 주지 않았으며, 각각의 stack 구조에서 가지고 있는 Cu, In, Ga, Se의 총량을 동일하게 유지하기 위하여 각 stack의 증착 시간을 동일하게 유지하였다. Selenization을 위한 RTP 조건은 550, $600^{\circ}C$ 각각에 대하여 1, 5, 10분으로 split을 진행하였다. Precursor stack의 증착 후 관찰한 XRD 결과는 비정질 상태를 잘 나타내었으며, SEM 결과 CIGS precursor stack을 제외한 나머지 구조의 stack에서는 In 박막의 surface roughness로 인하여 박막의 평탄화가 좋지 않음을 확인하였다. CIGS precursor stack의 경우, RTP 온도와 시간 split와 상관없이 결정화가 잘 이루어졌으나 grain의 성장이 부족하였다. 이에 비하여 CIG/Se, CuGa/In/Se, In/CuGa/Se 구조의 precursor stack의 경우, $550^{\circ}C$ 열처리에서는 InSe의 결정상이 관찰 되었으며 $600^{\circ}C$, 5분 이상 열처리에서 CIGS 결정상이 관찰되었다. 이러한 결과는 Se이 metal 원소들과 함께 있는 CIGS 구조에 비하여 metal precursor stack 위에 Se을 증착한 stack 구조들의 경우는 CIGS 결정을 형성하기 위해 Se이 metal 층들로 확산되어 반응을 하여야 하므로 상대적으로 많은 열에너지가 필요한 것으로 이해할 수 있으며, RTP를 이용한 selenization 공정으로 CIGS 박막 태양전지의 흡수층 형성이 가능함을 확인하였다.