• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.141-149
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• 1998

The W thin films were deposited on Si3N4 by a PECVD technique. The effects of substrate temperature and gas flow ratio on the properties of the W films were investigated. The deposition of W films were limited by surface reaction at the temperature range of 150>~$250^{\circ}C$, W films had the deposition rate of 150~530 $\AA$/min and stress of 0.85~$14.35\times10 ^9 \textrm {dynes/cm}^2}$ at various substrate temperatures and $SiH_4/WF_6$ flow ratios. $SiH_4/WF_6$ flow ratio affected the deposition rate and stress of the W films, expecially, excessive flow of SiH4 abruptly changed the structure, chemical bonding, and stress of the W films. Among the deposited W films on TiN, Ti, Mo, NiCr and Al adhesion layer, the one on the Al had the best adhesion property.

• Korean Journal of Materials Research
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• v.10 no.8
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• pp.575-580
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• 2000

Diamond thin films were deposited on $Si_3N_4$, SiC, TiC and $Al_2O_3$, substrates by the CVD method using Ta(TaC)Filament, and the appearance of the diamond films and their adhesion properties were examined by SEM, optical microscopy, indentation test and compression topple test. Diamond films were deposited at lower $CH_4$ concentration than 5%$CH_4$ for all kinds of the substrate material, but graphitic(amorphous)carbon was observed at 10%$CH_4$. The diamond film of about $12\mu\textrm{m}$ thickness on WC substrate partly peeled off, but the film on $Si_3N_4$ substrate held good adhesion. The indentation test showed that roughly ground surface was very effective for adhesion of diamond films to substrate. The topple test revealed that film thickness was an important factor governing the adhesion of the diamond film.

• Journal of the Speleological Society of Korea
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• no.76
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• pp.61-66
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• 2006

The present report is the investigation of the effects of the HIP treatment on plasma-sprayed ceramic coating of $Al_2O_3$, $Al_2O_3-SiO_2$ on the metal substrate. These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.162-162
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• 2017

AlCrN 코팅은 높은 경도, 낮은 표면 조도 등의 상온에서의 우수한 기계적 특성 이외에 고온에서 안정한 합금상의 형성으로 인하여 우수한 내열성을 보이는 코팅이며, Si을 첨가하여 나노복합구조를 갖는 AlCrSiN 코팅은 고경도 특성을 나타내는 나노결정립과 고내열성을 나타내는 $Si_3N_4$ 비정질이 동시에 존재함으로써 뛰어난 고온 특성까지 보유하여 공구 코팅으로의 적용 가능성이 크다. 본 연구에서는, 가혹화된 공구사용 환경 대응 하는 더욱 우수한 내마모성 및 내열성을 보이는 코팅막을 개발하기 위해 AlCrN/AlCrSiN 이중층 코팅을 합성하였다. 합성된 코팅의 구조 및 물성을 분석하기 위해 field emission scanning electron microscopy(FE-SEM), nano-indentation, atomic force microscopy(AFM) 및 ball-on-disk wear tester를 사용하였다. 내열성을 확인하기 위하여 코팅을 furnace에 넣어 500, 600, 700, 800, 900도에서 30분 동안 annealing한 후에 nano-indentation을 사용하여 경도를 측정을 하였다. 5:5, 7:3, 9:1의 두께 비율로 AlCrN/AlCrSiN 이중층 코팅을 합성하였으며 모든 코팅의 두께는 $3{\mu}m$로 제어되었다. AlCrN 코팅층의 두께가 증가할수록, 이중층 코팅의 경도 및 내마모성은 점차 향상되었지만 코팅의 밀착력은 감소하였다. 일반적으로 AlCrN 코팅은 상대적으로 높은 잔류응력을 갖고 있으므로, AlCrN 층의 두께비율이 증가함에 따라 코팅내의 잔류응력이 높아져 코팅의 경도는 증가하고 밀착특성은 낮아진 것으로 판단된다. AlCrSiN 상부층 공정시 기판 바이어스 전압을 -50 ~ -200V 로 증가시키면서 이중층 코팅을 합성하였다. XRD 분석 결과, 공정 바이어스 전압이 증가함에 따라 AlCrSiN 상부층은 점차 비정질화 되었고, 코팅의 경도와 표면 특성이 향상되는 것을 확인하였다. 이러한 특성 향상은 높은 바이어스 인가가 이온 충돌효과의 증가를 야기시켰으, 이로 인해 치밀한 코팅층 합성에 의한 결과로 판단된다. AlCrN/AlCrSiN 이중층 코팅을 어닐링 한 후 경도 분석 결과, -150, -200V에서 합성한 코팅은 900도 이상에서 26GPa 이상의 높은 경도를 보인 것으로 보아 우수한 내열성을 갖는 것으로 확인 되었다. 이는 AlCrSiN 상부층의 높은 Si 함량 (11at.%) 으로 인한 충분한 $Si_3N_4$ 비정질상의 형성과, 고바이어스 인가로 인한 AlCrN 결정상과 $Si_3N_4$ 비정질상의 고른 분배가 코팅의 내열성을 향상시키는데 기여를 한 결과로 판단된다.

• International Journal of Ocean System Engineering
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• v.2 no.2
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• pp.106-115
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• 2012

In the present study, TiN and CrN films were coated by arc ion plating equipment onto aluminum alloy substrate, A2024. The film thickness was about 4.65 ${\mu}m$. TiN and CrN films were analyzed by X-ray diffraction and energy dispersive X-ray equipments. The Young's modulus and the micro-Vickers hardness of aluminum substrate were modified by the ceramic film coatings. The difference in Young's modulus between substrate and coating film would affect on the wear resistance. The critical load, Lc, was 75.8 N for TiN and 85.5 N for CrN. It indicated from the observation of optical micrographs for TiN and CrN films that lots of cracks widely propagated toward the both sides of scratch track in the early stage of MODE I. TiN film began to delaminate completely at MODE II stage. The substrate was finally glittered at MODE III stage. For CrN film, a few crack can be observed at MODE I stage. The delamination of film was not still occurred at MODE II and then was happened at MODE III. This agrees with critical load measurement which the adhesive strength was greater for CrN film than for TiN film. Consequently, it was difficult for CrN to delaminate because the adhesive strength was excellent against Al substrate. The wear process, which the film adheres and the ball transfers, could be enhanced because of the increase in loading. The wear weight of ball was less for CrN than for TiN. This means that the wear damage of ball was greater for TiN than for CrN film. It is also obvious that it was difficult to delaminate because the CrN coating film has high toughness. The coefficient of friction was less for CrN coating film than for TiN film.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2420-2424
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• 2009

We have successfully demonstrated of metal-insulator-semiconductor (MIS) capacitors with $Al_2O_3/p-Si$ structures. The $Al_2O_3$ film was grown at $200^{\circ}C$ on H-terminated Si wafer by atomic layer deposition (ALD) system. Trimethylaluminum [$Al(CH_3)_3$, TMA] and $H_2O$ were used as the aluminum and oxygen sources. A cycle of the deposition process consisted of 0.1 s of TMA pulse, 10 s of $N_2$ purge, 0.1 s of $H_2O$ pulse, and 60 s of $N_2$ purge. The 5 nm thick $Al_2O_3$ layer prepared on Si substrate by ALD exhibited excellent electrical properties, including low leakage currents, no mobile charges, and a good interface with Si.

• Journal of Sensor Science and Technology
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• v.5 no.5
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• pp.79-84
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• 1996

A $1\;{\mu}m$ thick n-type GaAs layer with Si doping density of $1{\times}10^{17}/cm^{3}$ and a $500{\AA}$ thick undoped single crystalline AlAs layer were subsequently grown by molecular beam epitaxy on the $n^{+}$ GaAs substrate. The AlAs/GaAs layer was oxidized in $N_{2}$ bubbled $H_{2}O$ vapor($95^{\circ}C$) ambient at $400^{\circ}C$ for 2 and 3 hours. From the result of XPS analysis, small amounts of $As_{2}O_{3}$, AlAs, and elemental As were found in the samples oxidized up to 2 hours. After 3 hours oxidation, however, various oxides related to As were dissolved and As atoms were diffused out toward the oxide surface. The as-grown AlAs/GaAs layer was selectively converted to $Al_{2}O_{3}/GaAs$ at the oxidation temperature $400^{\circ}C$ for 3 hours. The oxidation temperature and time is very critical to stop the oxidation at the AlAs/GaAs interface and to form a defect-free surface layer.

• Journal of Powder Materials
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• v.26 no.5
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• pp.395-404
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• 2019

Aluminum nitride (AlN) has excellent electrical insulation property, high thermal conductivity, and a low thermal expansion coefficient; therefore, it is widely used as a heat sink, heat-conductive filler, and heat dissipation substrate. However, it is well known that the AlN-based materials have disadvantages such as low sinterability and poor mechanical properties. In this study, the effects of addition of various amounts (1-6 wt.%) of sintering additives $Y_2O_3$ and $Sm_2O_3$ on the thermal and mechanical properties of AlN samples pressureless sintered at $1850^{\circ}C$ in an $N_2$ atmosphere for a holding time of 2 h are examined. All AlN samples exhibit relative densities of more than 97%. It showed that the higher thermal conductivity as the $Y_2O_3$ content increased than the $Sm_2O_3$ additive, whereas all AlN samples exhibited higher mechanical properties as $Sm_2O_3$ content increased. The formation of secondary phases by reaction of $Y_2O_3$, $Sm_2O_3$ with oxygen from AlN lattice influenced the thermal and mechanical properties of AlN samples due to the reaction of the oxygen contents in AlN lattice.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.56-61
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• 1997

I $n_{0.53}$G $a_{0.47}$As/I $n_{0.52}$A $l_{0.48}$As pseudomorphic high electron mobility transistor (P-HEMT) structures were grown on semi-insulating InP substrates by molecular beam epitzxy method. The hall effect measuremetn was used to measure the electrical properties and the photoluminescence (PL) measurement was used to measure the electrical properties and the photoluminescence(PL) measurement for optical propety. By the cross-sectional transmission electron microscopy (XTEM) investigation of the V and X shape defects including slip with angle of 60.deg. C and 120.deg. C to surface in the sampel, the defects formation mecahnism in the I $n_{0.52}$A $l_{0.48}$As epilayers on InP substrates could be explained with the different thermal expansion coefficients between I $n_{0.52}$A $l_{0.48}$As epilayers and InP substrate.d InP substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.336-339
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• 2003

The present report is the investigation of the effects of the HIP treatment on plasma-sprayed ceramic coating of $Al_2O_3$, $Al_2O_3-SiO_2$ on the metal substrate. These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing.