• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.43-50
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• 2007

We have investigated the electro-optical characteristics and reliability of LEDs with the Indium-Tin-Oxide (ITO) electrodes formed by different deposition methods: electron beam evaporation, sputtering, and hybrid method of electron beam evaporation and subsequent sputtering. The deposition method of the ITO electrode has significant influence on the electro-optical characteristics and reliability of LEDs. The LEDs with the ITO electrodes formed by sputtering and electron beam evaporation have problems caused by sputtering damage and increased electrical resistance, respectively, and the problems have been solved by the hybrid method.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.195-199
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• 2011

Mo thin films were deposited on soda lime glass at room temperature by using DC magnetron sputtering The electrical and structural properties of the films were investigated by varying DC power and gas pressure as the deposition parameter. As DC power increased, the deposition rate of Mo films was increased and the electrical resistivity was decreased. It was observable that the crystallinity of the films was improved with increasing DC power. As gas pressure decreased, the deposition rate and resistivity of the films were decreased, and long rectangular grains were densely formed. With increasing gas pressure, the grains were transformed to a round shape and the voids on the film surface were increased. It was confirmed that the electrical resistivity of Mo films was increased as the amount of oxygen combined with Mo atoms increased. It was also disclosed that the films have low resistivity as the degree of coupling of oxygen with Mo was reduced due to the enhancement of the crystallinity of the films.

• Applied Microscopy
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• v.29 no.3
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• pp.265-274
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• 1999

The microstructure of Cu thin films in various deposition conditions was characterized. Cr films (50 nm thick) and Cu films (500 or 1000 nm thick) were deposited on polyimide films by DC magnetron sputtering. The Ar pressure during Cu deposition was controlled to 5, 50 and 100 mtorr. The microstructure was characterized using conventional and high resolution SEM and TEM. As sputtering pressure increases, open boundaries are observed more frequently. The Cu film deposited at 5 mtorr has a dense and uniform structure, while low-density regions or open boundaries between columns exist in the film deposited at higher pressure. As the film grows thicker, open boundaries are wider and the density of open boundaries are higher. The comparison between SEM and TEM show that the small features shown in high resolution SEM are grains. High resolution SEM is very effective to characterize the microstructure of the thin films. One column in the films deposited at 50 and 100 mtorr consists of several grains, which are smaller than those deposited at 5 mtorr.

• Journal of Surface Science and Engineering
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• v.38 no.4
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• pp.144-149
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• 2005

ZnO films were produced on the Si(100) and sapphire(0001) wafers by RF magnetron sputtering in terms of processing variables such as substrate temperature and RF power. The stress in films was obtained from the Stoney's formula using a laser scanning device. The stress levels in the films showed the range from $\~40$ MPa to $\~-1100$MPa depending on processing variables. The specimens were thermally cycled from R.T. to $250^{\circ}C$ to investigate the stress variation as a function of temperature. SEM was employed to characterize the microstructure of te films. As the substrate temperature increased, the film surface became rougher and the films showed coarser grains. The optical property o the films was studied by PL measurements. At the highest substrate temperature $800^{\circ}C$ the film exhibited sharper UV peaks unlike other conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.287-287
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• 2012

최근 투명 산화물 반도체(TOS: Transparent Oxide Semiconductor)중에 비정질 산화물 반도체(amorphous oxide semiconductor)를 이용한 트랜지스터 연구가 활발히 진행되고 있다. 비정질 산화물 반도체는 박막 트렌지스터 소자의 Active Layer으로 사용할 수 있다. 본 연구는 RF magnetron sputtering법으로 유리기판 위에 IGZO박막을 증착하였다. 박막 증착 조건은 초기 압력 $3.0{\times}10^{-6}$ Torr, 증착 압력 20 mTorr, 반응가스 Ar 50 sccm, RF power 30w, 증착 온도는 실온으로 고정하였으며, 공정변수로 증착 시간을 변화시키며 IGZO박막을 증착하였다. IGZO 타겟은 $In_2O_3$, $Ga_2O_3$, ZnO 분말을 각각 1:1:1 mol% 조성비로 혼합하여 소결한 타겟을 사용하였다. XRD 분석결과에 따라서 Bragg's 법칙을 만족하는 피크가 나타나지 않는 비정질 구조임을 확인할 수 있었다. 가시광 영역에서(450~700 nm) 모든 박막은 90% 이상 투과도를 나타내었다. 증착시간이 증가할수록 밴드갭이 감소하는 것을 확인하였다. 증착시간이 5분인 경우 캐리어 농도는 $2.2{\times}10^{19}$ $cm^{-3}$, 이동도는 7.5 $cm^2/V-s$, 비저항은 $3.8{\times}10^{-2}{\Omega}$-cm의 반도체 특성을 나타냈고, 박막 트렌지스터 소자의 Active Layer으로 사용할 수 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.244.2-244.2
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• 2014

금속, 플라스틱, 유리 등의 재료 표면에 다양한 색상을 표현하기 위해 일반적으로 습식 도금을 많이 적용하고 있다. 하지만 습식 도금은 공정 수가 많을 뿐만 아니라 위험물질 및 오염물질을 많이 사용하기 때문에 산업사고, 환경오염 등을 야기 시킨다. 따라서 본 연구에서는 친환경적 방법인 물리적기상증착(PVD ; Physical Vapor Deposition) 방식의 한 종류인 스퍼터링(Sputtering)으로 색상을 구현하였다. PVD 방식의 증착은 습식 도금 방식에 비해 친환경적이며, 전처리에서 후처리까지 한 공정으로 가능하다는 점이다. 스퍼터링은 PVD의 다른 방식인 E-beam 방식에 비해 대량생산을 할 수 있다는 장점이 있다. 양산형 스퍼터링 장비(${\Phi}1200mm{\times}H1400mm$)로 실험을 진행하였으며, 증착 물질은 Ti, Al, Cr 을 사용하였고, 반응성 가스(Reactive Gas) 로는 N2, C2H2 가스를 사용하였다. 전처리는 LIS (Linear Ion Source)로 식각(Etching) 하였고, 펄스직류전원공급장치(Pulsed DC Power Supply)를 사용하여 증착 하였으며, 증착시 기판에 bias (-100 V)를 인가 하였다. 그 결과 회색계열, 갈색계열 등 여러가지 색을 구현할 수 있었으며, 증착된 박막의 특성을 알아보기 위하여 색차계, 내마모 시험기, 연필경도 시험기를 사용하였다. 향후 후처리 공정으로 내지문(AF ; anti fingerprint coating) 박막 등과 같은 실용적인 박막을 증착할 계획이다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.772-777
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• 2018

This paper used RF Magnetron Sputtering to deposition n-type and p-type to ITO glass. The N-type ohmic contact worked well under all conditions. Sheet resistance has been shown to increase sheet resistance as RF Power increases. After analyzing the surface of the deposited thin film, in the condition that RF Power was 250W and substrate temperature was $250^{\circ}C$, particles were measured to have a uniform and consistent thin film. P-type has good ohmic contact under all conditions and sheet resistance has been shown to increase as RF Power increases. As the RF Power grew, thickness increased and stabilized. PN junction thin film and NP junction thin film showed increased thickness and stabilized as sputtering time increased. As a result of thin film, conversion efficiency was at 0.2 when sputtering time was 10 minutes.

• Journal of the Korean Magnetics Society
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• v.8 no.5
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• pp.261-269
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• 1998

Induced anisotropy with the energy of $6{\times}10^4\; J/m^3$ is obtained in amorphous Sm-Fe based thin films which are fabricated by rf magnetron sputtering under a magnetic field of 500~600 Oe. Compared with conventional thin films, the anisotropic thin films exhibit a similar "saturation" magnetostriction, but show a very large anisotropy in magnetorstiction which is of significant practical importance due to increased strain at a particular direction. It is shown from a systematic investigation over a wide composition range for binary Sm-Fe alloys that anisotropy is also induced, though small, during a normal sputtering procedure due to the stray field, and the largest anisotropy is observed in the composition range of 25~30 at.% Sm. Furthermore, induced anisotropy is also found to be formed by magnetic annealing, but the anisotropy energy is much smaller than that by magnetic sputtering. This may be because the volume diffusion by which atoms move during magnetic annealing to from induced anisotropy is much slower than the surface diffusion which is expected to be a dominant factor during magnetic sputtering.puttering.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.184.1-184.1
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• 2015

RF magnetron sputtering법을 이용하여 IGZO박막을 RF power 100W로 일정하게 유지시켜, 열처리 변화에 따른 구조적, 전기적, 광학적 특성 분석을 연구하였다. IGZO 타겟은 $In_2$ $O_3$, $Ga_2$ $O_3$, ZnO 분말을 각각 1:1:2 mol% 조성비로 혼합하여 소결한 타겟을 사용하였고, $20mm{\times}20mm$ XG glass 기판위에 IGZO박막을 증착하였다. sputtering의 조건은 base pressure $2.0{\times}$10^-6Torr, working pressure $2.0{\times}$10^-2Torr, RF power 100 W, 증착온도는 실온으로 고정, 증착된 박막은 Annealing장비로 $500^{\circ}C$, $700^{\circ}C$, $800^{\circ}C$로 열처리를 하였다. XRD 분석 결과 열처리 $700^{\circ}C$부터 2theta=31.4도에서 peak intensity가 증가하며 결정화가 진행되는 것을 확인하였다. AFM분석 결과 열처리 $700^{\circ}C$에서 최소 0.31 Roughness를 갖는 것을 확인하였고, Hall 측정 결과 열처리 $700^{\circ}C$에서 carrier concentration $4.91{\times}$10^19cm^-3, Mobility 14.4cm^2/V-s, Resistivity $8.7{\times}$10^-5${\Omega}-cm$로 확인하였으며, UV-Visible-NIR을 이용하여 열처리 한 모든 IGZO박막은 가시광선 영역에서 평균 85%이상의 광 투과성을 확인하였다.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.394-401
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• 2009

This paper reports the structural and optical properties of ZnO/glass thin films grown by radio-frequency magnetron sputtering with a powder target. In contrast to ZnO ceramic target typically used, a ZnO raw powder target was sputtered in this study. ZnO grew with the (0002) preferred orientation along the surface normal direction. Initially, the surface of ZnO thin films was flat considerably and then it became rougher as the thickness increased. The optical transmittance was as high as 88% in the range of 400-1000 nm. The bandgap energy of 3.23 eV at the 220 nm thick sample was estimated.