• Title, Summary, Keyword: TiAl

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Comparative Study of Texture of Al/Ti Thin Films Deposited on Low Dielectric Polymer and SiO$_2$Substrates (저 유전상수 폴리머와 SiO$_2$기판위에 형성된 Al/Ti박막의 우선방위 비교)

  • 유세훈;김영호
    • Journal of the Microelectronics and Packaging Society
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    • v.7 no.2
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    • pp.37-42
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    • 2000
  • The comparative study of texture of Al/Ti thin films deposited on low-dielectric polymer and $SiO_2$substrates has been investigated. Fifty-nm-thick Ti films and 500-nm-thick Al-1%Si-0.5%Cu (wt%) films were deposited sequentially onto low-k polymers and $SiO_2$by using a DC magnetron sputtering system. The texture of Al thin film was determined using X-ray diffraction (XRD) theta-2theta ($\theta$-2$\theta$) and rocking curve and the microstructure of Al/Ti films on low-k polymer and $SiO_2$substrates was characterized by cross-sectional transmission electron microscopy (TEM). Both the $\theta$-2$\theta$ method and rocking curve measurement suggest that Al/Ti thin films deposited on $SiO_2$have stronger texture than those deposited on low-k polymer. The texture of Al thin films strongly depended on that of Ti films. Cross-sectional TEM revealed that grains of Ti films on $SiO_2$substrates had grown perpendicular to the substrate, while the grains of Ti alms on SiLK substrates were formed randomly. The lower degree of (111) texture of Al thin films on low-k polymer was due to Ti underlayer.

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Effect of Ti Concentration on the Microstructure of Al and the Tunnel Magnetoresistance Behaviors of the Magnetic Tunnel Junction with a Ti-alloyed Al-oxide Barrier (Ti 첨가에 따른 Al 미세구조 변화 효과와 산화 TiAl 절연층을 갖는 자기터널접합의 자기저항 특성)

  • Song, Jin-Oh;Lee, Seong-Rae
    • Journal of the Korean Magnetics Society
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    • v.15 no.6
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    • pp.311-314
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    • 2005
  • We investigated the composition dependence of the tunneling magnetoresistance (TMR) behavior and the stability of the magnetic tunnel junctions (MTJs) with TiAlOx barrier and the microstructural evolution of TiAl alloy films. The TMR ratio increased up to $49\%$ at $5.33\;at\%$ Ti. In addition, a significant tunneling magnetoresistance (TMR) value of $20\%$ was maintained after annealing at $450^{\circ}C$, and the breakdown voltage ($V_B$) of and 1.35 V were obtained in the MTJ with $5.33\;at\%$ Ti-alloyed AlOx barrier. These results were closely related to the enhanced quality of the barrier material microstructure in the pre-oxidation state. Ti alloying enhanced the barrier/electrode interface uniformity and reduced microstructural defects. These structural improvements enhanced not only the TMR effect but also the thermal and electrical stability of the MTJs.

Effect of Collagen Treatment on Bioactivity of Ti-6Al- 7Nb and Ti-6Al-4V Alloys (Ti-6Al-7Nb and Ti-6Al-4V 합금의 생체활성에 미치는 콜라겐 처리의 영향)

  • Kim, Tae-Ho;Lee, Kap-Ho;Hong, Sun-Ig
    • Journal of the Korean Ceramic Society
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    • v.45 no.10
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    • pp.638-643
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    • 2008
  • Biomimetic apatite formation and deposition behaviors of Ti-6Al-7Nb and Ti-6Al-4V plates in simulated body fluids(SBF) under various conditions were examined. In case of regular samples without collagen treatments the weight gain due to apatite precipitation on the surface in Ti-6Al-4V was found to be higher than in Ti-6Al-7Nb. In case of collagen-coated samples, the weight gain in Ti-6Al-4V continued to be higher than in Ti-6Al-7Nb, but the difference between the two became smaller. Both Ti-6Al-7Nb and Ti-6Al-4V samples with collagen coating exhibited an appreciable increase of weight gain, which may be caused by the interaction between collagen and $Ca^{+2}$ ions. The weight gain was found to be not much affected by the addition of collagen to SBF. The ill-defined granular structure in the presence of collagen can be associated with the increasing volume fraction of amorphous calcium phosphate.

Corrosion Characteristics of $Al_3Ti-Cr$ Intermetallics (금속간 화합물 $Al_3Ti-Cr$의 부식특성)

  • Yu, Yong-Jae;Kim, Seong-Hun;Choe, Yun-Je;Kim, Jeong-Gu;Lee, Dong-Bok
    • Korean Journal of Materials Research
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    • v.10 no.6
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    • pp.398-402
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    • 2000
  • Three kinds of $Al_3Ti-Cr$ alloys, namely, $Al_{67}Ti_{25}Cr_8,\;Al_{66}Ti_{24}Cr_{10}\;and\;Al_{59}Ti_{26}Cr_{15}$, were prepared by induction melting followed by the thermomechanical treatment. The corrosion behavior in 3.5% NaCl solution and the high-temperature oxidation behavior at 1000, 1100 and $1200^{\circ}C$ for the prepared alloys were investigated. Electrochemical results indicated increased resistance to localized corrosion with increasing Cr content. Cr additions were found to prevent passive film from undergoing brittle fracture. XPS results revealed the passive films of $Al_3Ti-Cr$ alloys were composed mainly of $Al_2O_3$ that coexisted with $TiO_2$ and $Cr_2O_3$. The overall oxidation resistance of the prepared alloys were excellent. Specifically, the oxidation resistance increased in the order of $Al_{59}Ti_{26}Cr_{15},\;Al_{66}Ti_{24}Cr_{10}\;and\;Al_{67}Ti_{25}Cr_8$. As the Al content in the base alloys increased, the $Al_2O_3$ formation was facilitated leading to the increased oxidation resistance.

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Thermal Stability of TiN/Ti Barrier Metals with Al Overlayers and Si Substrates Modified under Different Annealing Histories (형성조건에 따른 TiN/Ti Barrier Metal의 Al 및 Si 과의 열적 안정성)

  • 신두식;오재응;유성룡;최진석;백수현;이상인;이정규;이종길
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.7
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    • pp.47-59
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    • 1993
  • The thermal stability of "stuffed" TiN/Ti barrier matals with different annealing history has been studied to improve the contact reliability of Al/Si contacts in 16M DRAM. The annealing conditions before the Al deposition such as film thickness, the annealing temperature and the annealing ambient have been varied. For TiN(900A)/Ti(300A) annealed at 450 in nitrogen ambient to form a "stuffed barrier" by inducing oxygen atoms into grain boundaries, there is no observation of Al penetrations into Si substrates after the post heat treatment of up to 700 even though there are massive amounts of Al found in TiN film after the post heat treatment of 600 indicating that TiN has a "sponge-like" function due to its ability to absorb several amounts of aluminum at elevated temperature. The TiN/Ti diffusion barrier annealed at 550 has, however, failed after the post heat treatment at 600. The thinner diffusion barriers with TiN(300A)/Ti(100A) failed after the post heat treatment at 600.he post heat treatment at 600.

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The microstructure and adhesive characteristics of Ti-Al-V-N films prepared by reactive magnetron sputtering (반응성 마그네트론 스퍼터링법으로 제조한 Ti-Al-V-N 박막의 미세조직 및 부착특성에 관한 연구)

  • Sohn, Yong-Un;Lee, Young-Ki
    • Journal of the Korean Society for Heat Treatment
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    • v.12 no.3
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    • pp.199-205
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    • 1999
  • The quaternary Ti-Al-V-N films have been grown on glass substrates by reactive dc and rf magnetron sputter deposition from a Ti-6Al-4V target in mixed Ar-$N_2$ discharges. The Ti-Al-V-N films were investigated by means of X-ray diffraction(XRD), electron probe microanalysis(EPMA) and scratch tester. Both XRD and EPMA results indicated that the Ti-Al-V-N films were of single B1 NaCl phase having columnar structure with the (111) preferred orientation. Scratch tester results showed that the adhesion strength of Ti-Al-V-N films which treated with substrate heating and vacuum annealing was superior to that of as-deposited film. The good adhesion strength was also achieved in the double-layer structure of Ti-Al-V-N/Ti-Al-V/Glass.

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Effect of Fe on the High Temperature Oxidation of TiAl Alloys (TiAl 합금의 고온 산화에 미치는 Fe의 영향)

  • 김미현;이동복
    • Journal of the Korean institute of surface engineering
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    • v.33 no.4
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    • pp.281-288
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    • 2000
  • To understand the effect of Fe on the oxidation behavior of TiAl alloys, TiAl-(2, 4, 6at% )Fe were oxidized at 800 and 90$0^{\circ}C$ in air. The oxidation resistance of TiAl-Fe alloys increased with increasing an iron content. The scales formed consisted of an outer $TiO_2$ layer, an intermediate $A1_2$$O_3$ layer, and an inner mixed ($TiO_2$+$A1_2$$O_3$) layer, being similar to other common TiAl alloys. But, the scales formed on TiAl-Fe alloys were generally thin compared to those formed on pure TiAl, and contained dissolved iron. Below the oxide scale, an oxygen affected zone was formed. This beneficial effects of Fe on increasing the oxidation resistance and scale adherence of TiAl alloys were attributed to the refinement of oxide grains, increased scale adherence and the enhanced alumina-forming tendency.

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Properties of AlTiN Films by Cathodic Arc Deposition (음극 아크 증착으로 제조된 AlTiN 박막의 물리적 특성)

  • Yang, Ji-Hun;Song, Min-A;Jeong, Jae-Hun;Kim, Seong-Hwan;Jeong, Jae-In
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.24-24
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    • 2014
  • 음극 아크 증착을 이용하여 제조한 AlTiN 박막의 공정 변화에 따른 물리적 특성 변화를 평가하였다. 또한 빗각 증착을 적용하여 제조한 AlTiN 박막의 특성을 평가하였다. Al-Ti 타겟(Al:Ti=75:25 at.%)을 음극 아크 소스에 장착하여 AlTiN 박막을 코팅하였다. 기판은 stainless steel(SUS304)과 초경(tungsten carbide; WC)을 사용하였다. 음극 아크 소스에 인가되는 전류가 낮을수록 AlTiN 박막 표면에 존재하는 거대입자의 밀도가 낮아졌으며, 공정 압력과 기판 전압이 높을수록 AlTiN 박막의 표면에 존재하는 거대입자의 밀도가 낮아지는 경향을 보였다. 코팅 공정 중 질소 유량을 변화했지만 AlTiN 박막의 특성은 변하지 았았다. AlTiN 박막 제조 시 빗각을 적용한 결과, $60^{\circ}$의 빗각을 적용한 다층 박막에서 약 33 GPa의 경도를 보였다. AlTiN 박막의 내산화성을 평가한 결과, $600^{\circ}C$이상에서 안정된 내산화성을 확인할 수 있었다.

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Observation of the Second Phases in a Red Phosphor $SrTiO_3$:Pr,Al by using Transmission Electron Microscopy ($SrTiO_3$:Pr,Al 적색 형광체에서 TEM을 이용한 2차상의 관찰)

  • 이정용;이호성;정연철;전덕영
    • Journal of the Korean Ceramic Society
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    • v.38 no.3
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    • pp.225-230
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    • 2001
  • 저전압용 형광체로 주목받고 있는 SrTiO$_3$:Pr,Al 형광체를 고상반응법으로 제조하였다. 부활성체 Al이 23 mol% 첨가되었을 때 SrTiO$_3$:Pr 형광체는 최대 발광 강도를 보여주었다. 최대 발광 강도를 보인 형광체에 대해 제한시야회절상과 투과전자현미경을 이용하여 SrTiO$_3$:Pr,Al 적색 형광체내 2차상 형성에 대한 연구를 행하였고 또한 에너지 분산 분광 분석을 행하여 SrTiO$_3$:Pr,Al 형광체내 주입된 부활성제 Al의 함량을 결정하였다. 제한시야회절상의 결과에 의하면 SrTiO$_3$:Pr,Al 적색 형광체내에 단사정 SrAl$_2$O$_4$, 삼사정 Ti$_4$O$_{7}$, 육방정 SrAl$_{12}$O$_{19}$가 2차상으로 존재함을 보여 주었다. 에너지 분산 분광 분석 결과 부활성제 Al의 함량 중 일부는 SrTiO$_3$:Pr,Al 적색 형광체 격자에 고용되고 일부 Al은 SrAl$_{12}$O$_{19}$와 SrAl$_2$O$_4$의 2차상을 형성하는데 소모됨을 보여주었다.주었다.

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Convenient Aluminizing Process of Steel by Using Al-Ti Mixed Powder Slurry (Al-Ti 혼합 분말 슬러리를 이용한 강의 알루미나이징처리 방법)

  • Lee, Young-Ki;Kim, Jung-Yeul;Lee, You-Kee
    • Korean Journal of Materials Research
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    • v.19 no.4
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    • pp.207-211
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    • 2009
  • In this study, we attempted to develop a convenient aluminizing process, using Al-Ti mixed slurry as an aluminum source, to control the Al content of the aluminized layer as a result of a one-step process and can be widely adopted for coating complex-shaped components. The aluminizing process was carried out by the heat treatment on disc and rod shaped S45C steel substrates with Al-Ti mixed slurries that were composed of various mixed ratios (wt%) of Al and Ti powders. The surface of the resultant aluminized layer was relatively smooth with no obvious cracks. The aluminized layers mainly contain an Fe-Al compound as the bulk phase. However, the Al concentration and the thickness of the aluminized layer gradually decrease as the Ti proportion among Al-Ti mixed slurries increases. It has also been shown that the Al-Ti compound layer, which formed on the substrate during heat treatment, easily separates from the substrate. In addition, the incorporation of Ti into the substrate surface during heat treatment was not observed.