• 한국재료학회지
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• 제26권10호
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• pp.542-548
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• 2016

The influence of NiCrAlY bond coating on the adhesion properties of an Fe thermal coating sprayed on an Al substrate was investigated. By applying a bond coat, an adhesion strength of 21MPa was obtained, which was higher than the 15.5MPa strength of the coating without the bond coat. Formation of cracks at the interface of the bond coat and the Al substrate was suppressed by applying the bond coat. Microstructural analysis of the coating interface using EBSD and TEM indicated that the dominant bonding mechanism was mechanical interlocking. Mechanical interlocking without crack defects in the coating interface may improve the adhesion strength of the coating. In conclusion, the use of an NiCrAlY bond coat is an effective method of improving the adhesion properties of thermal sprayed Fe coatings on Al substrates.

• 전자공학회논문지 IE
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• 제43권2호
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• pp.7-10
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• 2006

일반적인 산화 절연 게이트 대신 $BaTa_2O_6$를 사용한 GaN metal-insulator-semiconductor(MIS) 구조를 제작하였다. $Al_2O_3$(0001) 기판 위에서와 GaAs(001) 기판 위에서의 GaN 막의 누설 전류는 각각 $10^{-12}-10^{-13}A/cm^2$와 $10^{-6}-10^{-7}A/cm^2$로 측정되었다. 이 막의 누설전류는 각각 $Al_2O_3$(0001) 기판 위의 GaN인 경우는 45 MV/cm가 넘는 공간전하 제한전류에 의하여, GaAs(001) 기판 위의 GaN인 경우는 Poole-Frenkel 방출에 따른다는 것을 확인하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.288-292
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• 2003

AlM thin film has been deposited on A1$_2$O$_3$ substrate by reactive radio frequency(RF) magnetron sputtering method under various operating conditions such as working pressure, fraction of nitrogen partial pressure, and substrate temperature. Scanning Electron Microscope(SEM), X-ray Diffraction(XRD), and Atomic Force Microscope(AFM) have been measured to find out structural properties and preferred orientation of AlN thin films. SAW velocity of IDTs/AlN/Si structure was about 5038［㎧］ at the center frequency of 251.9［MHz］ and insertion loss was measured to be relatively low value of 35.6［dB］. SAW velocity of IDTs/AlN/A1$_2$O$_3$ structure was improved to be about 5960［㎧］ at the center frequency of 296.7［MHz］.

• 한국재료학회지
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• 제31권12호
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• pp.697-703
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• 2021

Aluminum nitride having a dense hexagonal structure is used as a high-temperature material because of its excellent heat resistance and high mechanical strength; its excellent piezoelectric properties are also attracting attention. The structure and residual stress of AlN thin films formed on glass substrate using TFT sputtering system are examined by XRD. The deposition conditions are nitrogen gas pressures of 1 × 10^-2, 6 × 10^-3, and 3 × 10^-3, substrate temperature of 523 K, and sputtering time of 120 min. The structure of the AlN thin film is columnar, having a c-axis, i.e., a <00·1> orientation, which is the normal direction of the glass substrate. An X-ray stress measurement method for crystalline thin films with orientation properties such as columnar structure is proposed and applied to the residual stress measurement of AlN thin films with orientation <00·1>. Strength of diffraction lines other than 00·2 diffraction is very weak. As a result of stress measurement using AlN powder sample as a comparative standard sample, tensile residual stress is obtained when the nitrogen gas pressure is low, but the gas pressure increases as the residual stress is shifts toward compression. At low gas pressure, the unit cell expands due to the incorporation of excess nitrogen atoms.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.96.2-96.2
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• 2010

The surface morphology and structural properties of polycrystalline silicon (poly-Si) films made in-situ aluminum induced crystallization at various substrate temperature (300~600) was investigated. Silicon films were deposited by hot-wire chemical vapor deposition (HWCVD), as the catalytic or pyrolytic decomposition of precursor gases SiH4 occurs only on the surface of the heated wire. Aluminum films were deposited by DC magnetron sputtering at room temperature. continuous poly-Si films were achieved at low temperature. from cross-section TEM analyses, It was confirmed that poly-Si above $450^{\circ}C$ was successfully grown on and poly-Si films had (111) preferred orientation. As substrate temperature increases, Si(111)/Si(220) ratio was decreased. The electrical properties of poly-Si film were investigated by Hall effect measurement. Poly-Si film was p-type by Al and resistivity and hall effect mobility was affected by substrate temperature.

• 전기학회논문지
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• 제66권8호
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• pp.1230-1235
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• 2017

We studied surface texture-etching of glass substrate by using reactive ion etching process with various working pressure (0.7~9.0 mT). With the increase in the pressure, a haze parameter, which means diffusive transmittance/total transmittance, was increased in overall wavelength regions, as measured by spectrophotometer. Also, atomic force microscopy (AFM) study also showed that the surface topography transformed from V-shaped, keen surface to U-shaped, flattened surface, which is beneficial for nanocrystalline silicon semiconductor growth with suppressing defective crack formation. The texture-etched ZnO:Al combined with textured glass exhibited pronounced haze properties that showed 60~90 % in overall spectral wavelength regions. This promising optical properties of double textured, transparent conducting substrate can be widely applied in silicon thin film photovoltaics and other optoelectronic devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.432-433
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• 2005

In this study, Al doped ZnO(AZO) thin film were prepared on glass substrates by FTS(Facing Targets Sputtering) system. We investigated electrical, optical and structural properties of AZO thin film with the substrate temperature of the R.T, $100^{\circ}C$, $200^{\circ}C$ and the post-annealing. The crystallinity of AZO thin film was increased with increasing the substrate temperature and post-annealing temperature $600^{\circ}C$. The remarkable change of the resistivity with the substrate temperature didn't found and the resistivity with post-annealing was increased slightly.

• 한국재료학회지
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• 제24권7호
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• pp.344-350
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• 2014

Metal films (i.e., Ti, Al and SUH310S) were prepared in a magnetron sputtering apparatus, and their cross-sectional structures were investigated using scanning electron microscopy. The apparatus used consisted of a cylindrical metal target which was electrically grounded, and two anode rings attached to the top and to the bottom of the target. A wire was placed along the center-line of the cylindrical target to provide a substrate. When the electrical potential of the substrate was varied, the metal-film formation rate depended on both the discharge voltage and the electrical potential of the substrate. As we made the magnetic field stronger, the plasma which appeared near the target collected on the plasma wall surface and thereby decreased the bias current. The bias current on the conducting wire was different from that for cation collection. The bias current decreased because the collection of cations decreased when we increased the magnetic-coil current. When the substrate was electrically isolated, the films deposited showed a slightly coarse columnar structure with thin voids between adjacent columns. In contrast, in the case of the grounded substrate, the deposited film did not show any clear columns but instead, showed a densely-packed granular structure. No peeling region was observed between the film and substrate, indicating good adhesion.

• 한국자기학회지
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• 제9권6호
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• pp.296-300
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• 1999

DC 마그네트론 스퍼터링 방법으로 금속 마스크를 사용하여 십자형태로 substrate/Ta/NiFe/FeMn/NiFe/CoFe/Al2O3/CoFe/NiFe와 substrate/Ta/NiFe/CoFe/Al2O3/CoFe/NiFe/FeMn/NiFe 스핀 터널링 접합 구조를 제조하였다. 이러한 구조에서 절연층(Al2O3)의 형성조건과 각 층의 두께와 파워에 대한 증착율에 변화를 주어 24.3%의 자기 저항비를 얻었다. 두 종류의 구조에 대한 자기적 특성 비교와 Corning glass 7059와 Si(111) 기판의 종류에 따른 결과를 비교하였으며 소자 제조때 수반되는 온도변화에 대한 특성변화를 알아보고자 열처리를 하였다. 열처리 결과 자기 저항비는 15$0^{\circ}C$까지는 어느 정도 일정한 값을 유지하다가 18$0^{\circ}C$ 열처리 후 갑자기 감소하는 결과를 얻었다.

• 한국표면공학회지
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• 제29권3호
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• pp.163-175
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• 1996

Flame-sprayed Ni-based coatings are investigated in order to improve the thermal fatigue properties of gray cast iron in the presence of water spraying. The results of thermal cycling tests from room temperature to $1100^{\circ}C$ indicate that thermal fatigue endurance is increased in the order of Ni-20%Cr, NiCr-6%Al, and Ni-5%Al. The thermal fatigue failure is caused by the formation of iron oxides between the coating and the substrate and then the thermal fatigue cracks have propagated either along the brittle iron oxide layer resulting in the spatting of the coatings in case of Ni-5%Al and NiCr-6%Al coatings or to the substrate resulting in the whole specimen fracture in case of Ni-20%Cr coating. It seems that the most governing factor for thermal fatigue resistance is the thermal expansion coefficient difference between the coating and the substrate. Microstructural variations before and after the tests are also discussed.