• 한국표면공학회지
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• 제32권3호
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• pp.401-405
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• 1999

Reflective silver films with high quality were prepared on polyester substrate by using sputter deposit on techniques. Best reflectivity thin films of silver were produced with process parameters of $10^{-6}$ Torr as base pressure, 50 W as R.F. power, 5 mTorr as working pressure, and 10 sccm as Ar flow rate. Being deposited with an R.F. power of 50 W, Ag films revealed the highest 96.3 % reflectance as illuminated with a light of 700 nm wavelength. The adhesion of sample films showed as high as 14 to $20{\;}kg/\textrm{cm}^2$, which is suitable for industrial purposes. Their film crystallinity and orientation resulted in the planes of (111) and (200) for the growth with a preferred orientation of <111>, in general. The cross-sections of thin film specimens showed columnar structures. It is noted that columns became coarsened and less dense as R.F. power increased, resulting in a low reflectivity for the product film.

• 한국세라믹학회지
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• 제38권10호
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• pp.942-947
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• 2001

MEMS 소자에의 응용을 위한 PZT(52/48) 박막을 diol을 용매로한 솔젤법에 의해 제조하였으며 미세구조에 따른 전기적 특성 및 압전 특성 관계를 고찰하였다. 0.5 mol 의 sol을 제작하여 1회 코팅시 $0.2{\mu}m$ 두께를 갖는 균열 없는 박막을 얻을 수 있었으며 $0.2{\mu}m$에서 $3.8{\mu}m$의 두께의 막을 증착하였다. 미세구조사진으로부터 층간 porous한 영역이 관찰되지 않음과 제2상의 성장이 없는 치밀한 columnar입자 성장을 확인 할 수 있었으며 균열없는 치밀화된 입자의 성장으로부터 우수한 이력곡선을 얻을 수 있었다. XRD분석으로부터 우선 배향성을 알아본 결과 (111)우선 배향성이 $1{\mu}m$ 영역까지 우세하다가 $1{\mu}m$이상의 두께에서 점차 random하게 바뀌는 것을 확인할 수 있었으며, 유전 특성 및 압전특성의 경향도 이와 유사하게 $1{\mu}m$ 영역까지 증가하다가 그 이상의 두께에서는 수렴하여 각각 1400, 300 pC/N 정도의 우수한 값을 가졌다.

• Corrosion Science and Technology
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• 제8권3호
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• pp.93-102
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• 2009

The direct-current electroetching of high purity aluminum in hot aqueous-chloride solution produces a high density of micrometer-wide tunnels whose walls are made up of the {100} planes and penetrate aluminum in the <100> directions at rates of micrometer per second. In the process of the alternating-current pitting of aluminum, cathodic polarization plays an important role in the nucleation and growth of the pits during the subsequent polarization. The direct-current tunnel etching and alternating-current etching of aluminum are basically related to the formation of poorly crystallized or amorphous passive films. If the passive film forms on the wall, a natural misfit exists between the film and the aluminum substrate, which in turn gives rise to stress in both the film and the substrate. Even though the amorphous films do not have directed properties, their stresses are influenced by the substrate orientation. The films on elastically soft substrate are likely to be less stressed and more stable than those on elastically hard substrate. The hardest and softest planes of aluminum are the {111} and {100} planes, respectively. Therefore, the films on the {111} substrates are most likely to be attacked, and those on the {100} substrates are least likely to be attacked. For the tunnel etching, it follows that the tunnel walls tend to consist of the {100} planes. Meanwhile, the tunnel tip, where active corrosion takes place, tend to be made of four closely packed {111} planes in order to minimize the surface energy, which gives rise to the <100> tunnel etching.

• 한국전기전자재료학회논문지
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• 제13권10호
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• pp.828-833
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• 2000

Growth characteristics and microstructure of AIN thin films grown by plasma assisted molecular beam epitaxy on Si substrates have been investigated. Growing temperature and substrate orientation were chosen as major variables of the experiment. Reflection high energy electron diffraction (RHEED), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the micorstructure of the films. On Si(100) substrates, AlN thin films were grown along the hexagonal c-axis preferred orientation at temperature range 850-90$0^{\circ}C$. However on Si(111), the AlN films were epitaxially grown with directional coherency in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112) at 85$0^{\circ}C$ and the epitaxial coherencry seemed to be slightly distorted with increasing temperature. The microstructure of AlN thin films on Si(111) substrates showed that the films include a lot of crystal defects and there exist micro-gaps among the columns.

• 한국결정성장학회지
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• 제19권2호
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• pp.70-74
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• 2009

Sol-gel 법으로 제조한 $Pb(Sc_{1/2}Nb_{1/2})O_3$(이하 PSN) sol을 이용하여 스핀 코팅법으로 Pt(111)/Ti/$SiO_2$/Si 기판위에 제조한 박막의 제조 공정에 따른 영향을 연구하였다. Pt 기판위에 PSN sol을 증착, 건조한 후에 $370^{\circ}C$에서 5분간 열처리를 행한 후 $10^{\circ}C/sec$의 급속 가열로 $600{\sim}700^{\circ}C$에서 최종 열처리한 경우에 박막은 (111)면으로 우선 배향하는 것으로 나타났다. 그러나 중간 열처리를 거치지 않고, 급속가열에 의한 최종 열처리만을 행한 경우에는 (100)면으로 우선 배향하는 것으로 나타났다. 한편, 중간 열처리 후 $4^{\circ}C/min$의 승온속도로 관상로에서 최종 열처리를 행한 경우에는 (111)면과 (100)면이 동시에 나타나는 것으로 나타났다. 동일한 조건하에서 박막의 두께는 모두 300로 중간 열처리 공정이 어떠한 영향도 미치지 않는 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.185-188
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• 2000

Crystal orientation of Ni$_{18}$ $Fe_{19}$ thin films prepared by facing targets sputtering system was investigated. FTS system can deposit a high quality thin film and control deposition conditions in wide range. T he crystallographic characteristics of Ni$_{18}$ $Fe_{19}$ thin films on variation of thickness and substrate tempera ture was investigated by XRD and AFM. As a result, we obtained Ni$_{18}$ $Fe_{19}$ thin films prepared at subst rate temperature room temperature, thickness 160nm and over revealed good crystal orientation to [111] direction.irection.

• 한국표면공학회지
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• 제34권2호
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• pp.151-160
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• 2001

The composition and the microstructure of the lead-tin alloy electrodeposited in a gluconate bath were invesitigated according to electrolysis conditions. The tin content of the lead-tin alloy electrodeposits increased with increasing current density and EDTA addition, while it decreased with increasing temperature and sodium gluconate concentration. The preferred orientation of the alloy deposits changed from the (220) plane through (200) to (200) + (111) planes with increasing cathode overpotential. The surface morphology of the films was closely related to both the preferred orientation and the alloy composition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.126-126
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• 2012

Copper is considered to be the most promising substrate, especially Cu(111), for the growth of high quality monolayer graphene. Since interactions between graphene and Cu substrates will influence on the orientation, quality, and electrical properties of synthesized graphene, we experimentally determine a weak interfacial interaction between Cu(111) substrate and graphene using angle-resolved photoemission spectroscopy (ARPES). The measurement was conducted from the initial stage to the formation of a graphene monolayer. Graphene growth was initiated along the Cu(111) lattice, and two rotated graphene domains were grown, where no significant differences were observed in the band structure depending on different orientations. The interaction, including electron transfer from the Cu(111) to graphene, was limited between the Shockley state of the Cu(111) surface and the ${\pi}$ bands of graphene. These results provide direct information on the growth behavior and interactions between the Cu(111) and graphene.

• 한국재료학회지
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• 제29권10호
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• pp.647-655
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• 2019

In order to analyze the effect of hot asymmetric rolling on the microstructure and texture of aluminum alloy and to investigate the effect of the texture on the formability and plastic anisotropy of aluminum alloy, aluminum 6061 alloy is asymmetrically rolled at room temperature, $200^{\circ}C$, $350^{\circ}C$, and $500^{\circ}C$, and the results are compared with symmetrically rolled results. In the case of asymmetric rolling, the equivalent strain (${\varepsilon}_{eq}$) is greatest in the upper roll part where the rotational speed of the roll is high and increases with increasing rolling temperature. The increase rate of the mean misorientation angle with increasing temperature is larger than that during symmetrical rolling, and dynamic recrystallization occurs the most when asymmetrical rolling is performed at $500^{\circ}C$. In the case of hot symmetric rolling, the {001}<110> rotated cube orientation mainly develops, but in the case of hot asymmetric rolling, the {111}<110> orientation develops along with the {001}<100> cube orientation. The hot asymmetric rolling improves the formability (${\bar{r}}$) of the aluminum 6061 alloy to 0.9 and reduces the plastic anisotropy (${\Delta}r$) to near zero due to the {111}<110> shear orientation that develops by asymmetric rolling.

• 대한금속재료학회지
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• 제49권12호
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• pp.995-1000
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• 2011

The microstructure of Cu-24 wt.%Ag filamentary nanocomposite fabricated by a thermo-mechanical process has been investigated by transmission electron microscopy (TEM) observations. This study is focused on the stability of Ag filaments formed by cold drawing; the effects of thermal treatment on the precipitation behavior and distribution of Ag-rich precipitates were also investigated. The Ag filaments elongated along the <111> orientation were observed in Cu-rich ${\alpha}$ phase of the as-drawn specimen and the copper matrix and the silver filament have a cube on cube orientation relationship. Annealing at temperatures lower than $200^{\circ}C$ for the as-drawn specimen caused insignificant change of the fibrous morphology but squiggly interfaces or local breaking of the elongated Ag filaments were easily observed with annealing at $300^{\circ}C$. When samples were annealed at $400^{\circ}C$, discontinuous precipitation was observed in supersaturated Cu solid solution. Ag precipitates with a thickness of 7-20 nm were observed along the <112> direction and the orientation relationship between the copper matrix and the Ag precipitates maintained the same orientation relationship in the as-drawn specimen. The interface between the copper matrix and the Ag precipitates is parallel to {111} and micro-twins were observed in the Ag precipitates.