• 제목/요약/키워드: aluminum oxide (Al2O3)

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Fe3Al, Fe3Al-Cr, Fe3Al-Cr-Mo, Ni3Al 및 Ni3Al-Cr 합금표면에 형성된 산화물 특성분석 (Characterization of Oxide Scales Formed on Fe3Al, Fe3Al-Cr, Fe3Al-Cr-Mo, Ni3Al and Ni3Al-Cr Alloys)

  • 심웅식;이동복
    • 한국재료학회지
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    • 제12권11호
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    • pp.845-849
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    • 2002
  • Alloys of $Fe_3$Al, $Fe_3$Al-6Cr, $Fe_3$Al-4Cr-1Mo, $Ni_3$Al, and $Ni_3$Al-2.8Cr were oxidized at $1000^{\circ}C$ in air, and the oxide scales formed were studied using XRD. SEM, EPMA, and TEM. The oxide scales that formed on $Fe_3$Al-based alloys consisted primarily of $\alpha$-$Al_2$$O_3$ containing a small amount of dissolved Fe and Cr ions, whereas those that formed on $Ni_3$Al-based alloys consisted primarily of $\alpha$-$Al_2$$O_3$, together with a small amount of $NiAl_2$$O_4$, NiO and dissolved Cr ions. For the entire alloys tested, nonadherent oxide scales formed, and voids were inevitably existed at the scale-matrix interface.

원자층 증착에 있어서 아르곤 펄스 시간이 Al2O3 박막에 미치는 효과 (Effects on the Al2O3 Thin Film by the Ar Pulse Time in the Atomic Layer Deposition)

  • 김기락;조의식;권상직
    • 반도체디스플레이기술학회지
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    • 제20권4호
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    • pp.157-160
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    • 2021
  • As an insulator for a thin film transistor(TFT) and an encapsulation material of organic light emitting diode(OLED), aluminum oxide (Al2O3) has been widely studied using several technologies. Especially, in spite of low deposition rate, atomic layer deposition (ALD) has been used as a process method of Al2O3 because of its low process temperature and self-limiting reaction. In the Al2O3 deposition by ALD method, Ar Purge had some crucial effects on the film properties. After reaction gas is injected as a formation of pulse, an inert argon(Ar) purge gas is injected for gas desorption. Therefore, the process parameter of Ar purge gas has an influence on the ALD deposited film quality. In this study, Al2O3 was deposited on glass substrate at a different Ar purge time and its structural characteristics were investigated and analyzed. From the results, the growth rate of Al2O3 was decreased as the Ar purge time increases. The surface roughness was also reduced with increasing Ar purge time. In order to obtain the high quality Al2O3 film, it was known that Ar purge times longer than 15 sec was necessary resulting in the self-limiting reaction.

PVT 법으로 성장 된 bulk AlN 단결정의 열 산화 공정에 관한 연구 (A study on the thermal oxidation process of bulk AlN single crystal grown by PVT)

  • 강효상;강승민
    • 한국결정성장학회지
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    • 제30권5호
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    • pp.168-173
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    • 2020
  • AlN의 열 산화 공정에서 발생하는 거동 및 메커니즘을 확인하기 위해 bulk AlN 단결정에 대해 대기분위기에서 온도에 따라 열처리를 수행하였다. 800℃의 온도에서 bulk AlN의 본격적인 산화 및 Al-oxide 들의 성장이 일어난 것을 확인하였고, 온도가 증가함에 따라 산소 성분의 wt%가 증가하는 반면 질소 성분의 wt%는 감소하는 경향을 보였다. 900℃에서 열처리하는 경우, 성장 된 Al-oxide은 이웃한 Al-oxide와 merging되어 α-Al2O3 다결정을 형성하기 시작했다. 1000℃의 온도에서 열처리하는 동안, 육각 피라미드 형 α-Al2O3 다결정이 명확히 형성되었음을 확인하였다. X-선 회절 패턴 분석을 통해 bulk AlN의 온도에 따른 표면 결정 구조의 변화를 자세히 조사하였다.

알루미늄 함량에 따른 알루미늄 주철의 내산화성에 관한 연구 (A Study on the Oxidation Resistance of Aluminum Cast Iron by Aluminum Content)

  • 김동혁
    • 한국주조공학회지
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    • 제40권6호
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    • pp.135-145
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    • 2020
  • Aluminum cast iron has excellent oxidation resistance, sulfurization resistance, and corrosion resistance. However, the ductility at room temperature is insufficient, and at temperatures above 600?, the strength drops sharply and practicality is limited. In the case of heat-resistant cast iron, high-temperature materials containing Cr and Ni account for 30 to 50% or more. However, these high-temperature materials are expensive. Aluminum heat-resistant cast iron is considered as a substitute for expensive heat-resistant materials. Oxidation due to the aging temperature and holding time conditions increases more in 0 wt.% Al-cast iron than in 2 and 4 wt.% Al-cast iron according to oxidized weight and gravimetric oxide layer thickness measurements. As a result of observing the cross-section of the oxide layer, it was found to contain 0 wt.% of Al-cast iron silicon oxide-containing SiO2 or Fe2SiO4 oxide film. In cast iron containing aluminum, the thickness of the internal oxide layer due to aluminum increases as the aging temperature and retention time increase, and the amount of the iron oxide layer generated on the surface decreases.

Corrosion behaviors of plasma electrolytic oxidation (PEO) treated high-silicon aluminum alloys

  • Park, Deok-Yong;Chang, Chong-Hyun;Oh, Yong-Jun;Myung, Nosang V.;Yoo, Bongyoung
    • 한국표면공학회지
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    • 제55권3호
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    • pp.143-155
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    • 2022
  • Ceramic oxide layers successfully were formed on the surface of cast Al alloys with high Si contents using plasma electrolytic oxidation (PEO) process in electrolytes containing Na2SiO3, NaOH, and additives. The microstructure of the oxide layers was systematically analyzed using scanning electron microscopy (SEM), cross-sectional transmission electron microscopy (TEM), X-ray diffraction patterns (XRD), and energy X-ray dispersive spectroscopy (EDS). XRD analysis indicated that the PEO untreated high-silicon Al alloys (i.e., 17.1 and 11.7 wt.% Si) consist of Al, Si and Al2Cu phases whereas Al2Cu phase selectively disappeared after PEO treatment. PEO process yielded an amorphous oxide layer with few second phases including γ-Al2O3 and Fe-rich phases. The corrosion behaviors of high-silicon Al alloys treated by PEO process were investigated using electrochemical impedance spectroscopy (EIS) and other electrochemical techniques (i.e., open circuit potential and polarization curve). Electroanalytical studies indicated that high-silicon Al alloys treated by PEO process have greater corrosion resistance than high-silicon alloys untreated by PEO process.

H2SO4 수용액에서의 주조용 알루미늄 합금들의 부식거동 (Corrosion Behavior of Casting Aluminum Alloys in H2SO4 Solution)

  • 우상현;손영진;이병우
    • 동력기계공학회지
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    • 제20권3호
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    • pp.17-21
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    • 2016
  • The corrosion behavior of aluminum alloys in the $H_2SO_4$ solution was investigated based on potentiodynamic techniques. Electrochemical properties, such as corrosion potential($E_c$), passive potential($E_p$), corrosion current density($I_c$), corrosion rate(mpy), of Al-Mg-Si, Al-Cu-Si and Al-Si alloys were characterized at room temperature. Passive aluminum oxide film, which including $Al_2(SO_4)_3$ and $3Al_2O_34SO_38H_2O$, were uniformly formed on the surface via the reaction of Al with $SO{_3}^{2-}$ or $SO{_4}^{2-}$ ions in the $H_2SO_4$ solution and the dependence of the corrosion behavior on the alloying element was discussed. The selective leaching of alloy element increased with increasing Cu content in the aluminum alloys.

Borate 완충용액에서 알루미늄의 산화피막의 생성과정과 전기적 성질에 대한 대기의 영향 (Atmospheric Effects on Growth Kinetics and Electronic Properties of Passive Film of Aluminum in Borate Buffer Solution)

  • 김연규
    • 대한화학회지
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    • 제60권3호
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    • pp.169-176
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    • 2016
  • Borate 완충용액에서 Al의 부식과 부동화에 관하여 변전위법, 대 시간 전류법 그리고 다중 주파수 전기화학적 임피던스 측정법으로 조사하였다. 공기 또는 산소의 영향은 환원과정에 영향을 주었지만 산화반응에는 영향을 미치지 못 하는 것으로 보인다. 부동화 영역에서 생성되는 피막의 전기적 성질은 Mott-Schottky 식이 적용되는 n-type 반도체 성질을 보였다. 낮은 전극전위에서 생성되는 Al의 산화피막은 Al(OH)3로 충분한 부동화 효과를 보이지 못하나, 전극전위가 증가하면서 Al2O3로 변하였다. Al2O3 피막은 “전기장에 의한-이온의 이동” 과정에 의하여 성장하는 것으로 보인다.

전하 포획 플래시 소자를 위한 Al2O3/La2O3/SiO2 다층 박막 구조의 메모리 특성 (Memory Characteristics of Al2O3/La2O3/SiO2 Multi-Layer Structures for Charge Trap Flash Devices)

  • 차승용;김효준;최두진
    • 한국재료학회지
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    • 제19권9호
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    • pp.462-467
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    • 2009
  • The Charge Trap Flash (CTF) memory device is a replacement candidate for the NAND Flash device. In this study, Pt/$Al_2O_3/La_2O_3/SiO_2$/Si multilayer structures with lanthanum oxide charge trap layers were fabricated for nonvolatile memory device applications. Aluminum oxide films were used as blocking oxides for low power consumption in program/erase operations and reduced charge transports through blocking oxide layers. The thicknesses of $SiO_2$ were from 30 $\AA$ to 50 $\AA$. From the C-V measurement, the largest memory window of 1.3V was obtained in the 40 $\AA$ tunnel oxide specimen, and the 50 $\AA$ tunnel oxide specimen showed the smallest memory window. In the cycling test for reliability, the 30 $\AA$ tunnel oxide sample showed an abrupt memory window reduction due to a high electric field of 9$\sim$10MV/cm through the tunnel oxide while the other samples showed less than a 10% loss of memory window for $10^4$ cycles of program/erase operation. The I-V measurement data of the capacitor structures indicated leakage current values in the order of $10^{-4}A/cm^2$ at 1V. These values are small enough to be used in nonvolatile memory devices, and the sample with tunnel oxide formed at $850^{\circ}C$ showed superior memory characteristics compared to the sample with $750^{\circ}C$ tunnel oxide due to higher concentration of trap sites at the interface region originating from the rough interface.

결정질 실리콘 태양전지를 위한 PA-ALD Al2O3 막의 패시베이션 효과 향상 연구 (Improvement on the Passivation Effect of PA-ALD Al2O3 Layer Deposited by PA-ALD in Crystalline Silicon Solar Cells)

  • 송세영;강민구;송희은;장효식
    • 한국전기전자재료학회논문지
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    • 제26권10호
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    • pp.754-759
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    • 2013
  • Aluminum oxide($Al_2O_3$) film deposited by atomic layer deposition (ALD) is known to supply excellent surface passivation properties on crystalline Si surfaces. Since $Al_2O_3$ has fixed negative charge, it forms effective surface passivation by field effect passivation on the rear side in p-type silicon solar cell. However, $Al_2O_3$ layer formed by ALD process needs very long process time, which is not applicable in mass production of silicon solar cells. In this paper, plasma-assisted ALD(PA-ALD) was applied to form $Al_2O_3$ to reduce the process time. $Al_2O_3$ synthesized by ALD on c-Si (100) wafers contains a very thin interfacial $SiO_2$ layer, which was confirmed by FTIR and TEM. To improve passivation quality of $Al_2O_3$ layer, the deposition temperature was changed in range of $150{\sim}350^{\circ}C$, then the annealing temperature and time were varied. As a result, the silicon wafer with aluminum oxide film formed in $250^{\circ}C$, $400^{\circ}C$ and 10 min for the deposition temperature, the annealing temperature and time, respectively, showed the best lifetime of 1.6ms. We also observed blistering with nanometer size during firing of $Al_2O_3$ deposited on p-type silicon.

Solution-Processed Al2O3 확산층을 이용한 Sputtering IZO Thin Film Transistor의 안정성 향상 (Improved Stability Sputtered IZO Thin Film Transistor Using Solution Processed Al2O3 Diffusion Layer)

  • 황남경;임유성;이정석;이세형;이문석
    • 한국전기전자재료학회논문지
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    • 제31권5호
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    • pp.273-277
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    • 2018
  • This research introduces the sputtered IZO thin film transistor (TFT) with solution-processed $Al_2O_3$ diffusion layer. IZO is one of the most commonly used amorphous oxide semiconductor (AOS) TFT. However, most AOS TFTs have many defects that degrade performance. Especially oxygen vacancy in the active layer. In previous research, aluminum was used as a carrier suppressor by binding the oxygen vacancy and making a strong bond with oxygen atoms. In this paper, we use a solution-processed $Al_2O_3$ diffusion layer to fabricate stable IZO TFTs. A double-layer solution-processed $Al_2O_3$-sputtered IZO TFT showed better performance and stability, compared to normal sputtered IZO TFT.