• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.1
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• pp.44-48
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• 2013

Niobium oxide($Nb_2O_5$) films were deposited on p-type Si wafers at room temperature using in-line pulsed-DC magnetron sputtering system with various frequencies. The different duty ratios were obtained by varying the frequency of pulsed DC power from 100 to 300 kHz at the fixed reverse time of $1.5{\mu}s$. From the thickness of the sputtered $NbO_x$ films, it was possible to obtain much higher deposition rate in case of pulsed-DC sputtering than RF sputtering. However, the similar leakage currents and structural characteristics were obtained from the metal-insulator-semiconductor(MIS) structure fabricated with the $NbO_x$ films and the x-ray photoelectron spectroscopy(XPS) results in spite of the different deposition rates. From the experimental results, the $NbO_x$ films sputtered by pulsed-DC sputtering are expected to be used in the fabrication process instead of RF sputtering.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.149-149
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• 2009

실제 산업에서 가장 많이 사용하고 있는 in-line type system에서 Al-doped ZnO (AZO) 막을 bipolar pulsed DC sputtering을 이용해 증착하였다. 약 30 nm/sec의 속도로 기판을 타겟 좌우로 swing 하면서 동적 증착 공정을 한 AZO 박막의 columnar structure가 정적 증착일 때와 다른 형태의 zigzag-type columnar structure가 형성되었다. 투명전도막의 가장 중요한 특성인 비저항과 투과도가 동적 증착 공정일 때의 박막과 정적 증착 공정일 때의 박막이 각각 $2.5{\times}10^{-3}{\Omega}{\cdot}cm$, 78.5%와 $1.65{\times}10^{-3}{\Omega}{\cdot}cm$, 83.9% 였다. 이렇게 성장하는 막의 구조 형태에 따라 달라지는 특성 변화는 양산하는 현장에서 매우 중요한 것이며, 동적 증착 공정에서의 박막 특성 개선에 정적 증착 공정과는 다른 방법의 연구가 필요할 것이다.

• Journal of Magnetics
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• v.17 no.4
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• pp.245-250
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• 2012

Ferromagnetic resonance and X-ray specular reflectivity measurements were performed on $Ni_{81}Fe_{19}/Ir_{20}Mn_{80}/Co_{90}Fe_{10}$ exchange bias trilayers, which were grown using the pulsed-DC magnetron sputtering technique on Si(100)/$SiO_2$(1000 nm) substrates, to investigate the evolution of the interface roughness and exchange bias and their dependence on the NiFe layer thickness. The interface roughness values of the samples decrease with increasing NiFe thickness. The in-plane ferromagnetic resonance measurements indicate that the exchange bias field and the peak-to-peak line widths of the resonance curves are inversely proportional to the NiFe thickness. Furthermore, both the exchange bias field and the interface roughness show almost the same dependence on the NiFe layer thickness. The out-of plane angular dependent measurements indicate that the exchange bias arises predominantly from a variation of exchange anisotropy due to changes in interfacial structure. The correlation between the exchange bias and the interface roughness is discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.304-308
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• 2013

For the application to the window layer of $Cu(In,Ga)Se_2$(CIGS) solar cell, zinc oxide(ZnO) thin film was deposited at various temperatures by in-line pulsed DC sputtering. From the structural, optical, and electrical investigation and analysis, it was possible to obtain the lower thickness, the lower resistivity, and the higher transmittance at a higher process temperature. The energy band gap of ZnO was calculated using the transmittance data and was analyzed in terms of the dependency on temperature. From the X-ray diffraction(XRD) results, it was possible to conclude that a dominant peak was found about $34.2{\sim}34.6^{\circ}$(111) and crystallinity was obtained at a temperature above $150^{\circ}C$.

• Journal of Surface Science and Engineering
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• v.55 no.6
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• pp.353-362
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• 2022

Recently, transmittance of photomasks for ultra-violet (UV) region is getting more important, as the light source wavelength of an exposure process is shortened due to the demand for technologies about high integration and miniaturization of devices. Meanwhile, such problems can occur as damages or the reduction of yield of photomask as electrostatic damage (ESD) occurs in the weak parts due to the accumulation of static electricity and the electric charge on chromium metal layers which are light shielding layers, caused by the repeated contacts and the peeling off between the photomask and the substrate during the exposure process. Accordingly, there have been studies to improve transmittance and antistatic performance through various functional coatings on the photomask surface. In the present study, we manufactured antireflection films of Nb₂O₅, | SiO₂ structure and antistatic films of ITO designed on 100 × 100 × 3 mmt sodalime glass by DC magnetron sputtering system so that photomask can maintain high transmittance at I-line (365 nm). ITO thin film deposited using In/Sn (10 wt.%) on sodalime glass was optimized to be 10 nm-thick, 3.0 × 103 𝛺/☐ sheet resistance, and about 80% transmittance, which was relatively low transmittance because of the absorption properties of ITO thin film. High average transmittance of 91.45% was obtained from a double side antireflection and antistatic thin films structure of Nb₂O₅ 64 nm | SiO₂ 41 nm | sodalime glass | ITO 10 nm | Nb₂O₅ 64 nm | SiO₂ 41 nm.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.194-194
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• 2010

태양전지용 투명전도막에 사용되는 Al-doped ZnO (AZO) 막은 저가이면서도 가시광역 영역에서 갖는 우수한 투과율과 낮은 비저항을 갖는 특성 때문에 ITO의 대체 재료로서 최근 활발한 연구가 진행되고 있다. 특히, 양산 현장에서는 in-line type의 대형 sputtering system에서 증착하고 있으며 높은 증착 속도와 박막 특성의 균일도가 중요한 과제다. 본 연구에서는 $2\;m\;{\times}\;1\;m\;{\times}\;0.2\;m$의 sputtering system에서 기판 캐리어를 이용해서 커다란 기판을 좁고 긴 타겟의 양쪽으로 왕복 운동을 하는 swing dynamic deposition 방법으로 $272\;mm\;{\times}\;500\;mm$ 크기의 AZO target (Al 2 wt%)을 이용하여 bipolar pulsed dc로 증착하였다. 이 시스템의 배기는 TMP와 cryo pump를 이용해서 $5\;{\times}\;10^{-7}\;Torr$의 기본 진공도를 얻으며, 공정 중에는 TMP만 사용하였다. 하지만, 본 시스템의 TMP는 비대칭 적으로 한쪽에 치우쳐 설치되어 있는데, 이것이 챔버 내에서 공정 가스인 Ar의 유동의 불균일도를 초래하게 되며, 그것이 증착되는 박막의 두께 균일도 및 특성 균일도에 영향을 주고 있음을 알 수 있었다. 본 연구에서는 다른 기본 진공도에서 증착된 AZO 박막의 특성 차이를 알아보고 비대칭 배기 구조가 in-line type 시스템에서 어떠한 두께 및 특성 불균일도를 가져오는지, 그리고 시스템 내부에 발생시키는 압력 불균일도를 상용 3차원 전산 유체해석 프로그램인 CFD-ACE+를 이용하여 분석하였다.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.89-93
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• 2017

For various process pressures, aluminum doped zinc oxide(AZO) films were deposited by in-line pulsed-DC sputtering. The deposited AZO films were optically and electrically investigated and analyzed for the window layers of CIGS solar cell systems. As the pressure was increased from 9 mtorr to 15 mtorr, the thickness of AZO was decreased as a result of scattering and its sheet resistance was rapidly increased. The transmittance of AZO was slightly decreased as the pressure was increased and the calculation of figure of merit(F.O.M) was dependent on the sheet resistance. The structural characteristics of AZO thin films analyzed by X-ray diffraction(XRD) showed no significant dependency according to the pressure.