• Title/Summary/Keyword: Si (111)

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Orientation Control of $SrBi_2Ta_2O_9$ Thin Films on Pt (111) Substrates

  • Lee, Si-Hyung;Lee, Jeon-Kook;Choelhwyi Bae;Jung, Hyung-Jin;Yoon, Ki-Hyun
    • The Korean Journal of Ceramics
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    • v.6 no.2
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    • pp.116-119
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    • 2000
  • The a-axis and c-axis prefer oriented SBT thin films could be deposited on Pt(111)/Ti/$SiO_2$$650^{\circ}C$). The c-axis preferred orientation of SBT film can be obtained by Sr deficiency and high compressive stress. However, the a-axis-oriented grains can be formed under stoichiometric Sr content and nearly stress-free state.

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Anisotropic Silicon Etching Using $RuO_2$ Thin Film as a Mask Layer by TMAH Solution ($RuO_2$를 마스크 층으로 TMAH에 의한 이방성 실리콘 식각)

  • 이재복;오세훈;홍경일;최덕균
    • Journal of the Korean Ceramic Society
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    • v.34 no.10
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    • pp.1021-1026
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    • 1997
  • RuO2 thin film has reasonably good conductivity and stiffness and it is thought to substitute for the cantilever beam made up of Pt and Si3N4 double layers in microactuators. Therefore, anisotopic Si etching was performed using RuO2 thin film as a mask layer in 25 wt. % TMAH water solution. In the etching temperature ranging from 6$0^{\circ}C$ to 75$^{\circ}C$, the etch rates of all the crystallographic directions increased linearly as the etching temperature increased. The etch rate ratio(selectivity) of [111]/[100] which varied from 0.08 to 0.14, was not sensitive to temperature. The activation energies for [110] direction, [100] direction and [111] direction were 0.50, 0.66 and 1.04eV, respectively. RuO2 cantilever beam with a clean surface was formed at the etching temperatures of 6$0^{\circ}C$ and $65^{\circ}C$. But the damages due to formation of pin holes on RuO2 surface were observed beyond 7$0^{\circ}C$. The tensile stress of RuO2 thin films caused the cantilever bending upward. As a result, it was demonstrated that the formation of conducting oxide RuO2 cantilever beam which can replace the role of an electrode and supporting layer could be possible by TMAH solution.

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MOCVD of GaN Films on Si Substrates Using a New Single Precursor

  • Song, Seon-Mi;Lee, Sun-Sook;Yu, Seung-Ho;Chung, Taek-Mo;Kim, Chang-Gyoun;Lee, Soon-Bo;Kim, Yun-Soo
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.953-956
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    • 2003
  • Hexagonal GaN (h-GaN) films have been grown on Si(111) substrates by metal organic chemical vapor deposition using the azidodiethylgallium methylamine adduct, Et₂Ga(N₃)·NH₂Me, as a new single precursor. Deposition was carried out in the substrate temperature range 385-650 °C. The GaN films obtained were stoichiometric and did not contain any appreciable amounts of carbon impurities. It was also found that the GaN films deposited on Si(111) had the [0001] preferred orientation. The photoluminescence spectrum of a GaN film showed a band edge emission peak characteristic of h-GaN at 378 nm.

Formation of $Al_O_3$Barrier in Magnetic Junctions on Different Substrates by $O_2$Plasma Etching

  • Wang, Zhen-Jun;Jeong, Won-Cheol;Yoon, Yeo-Geon;Jeong66, Chang-Wook;Joo, Seung-Ki
    • Journal of Magnetics
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    • v.6 no.3
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    • pp.90-93
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    • 2001
  • Co/$Al_O_3$/NiFe and CO/$Al_O_3$/Co tunnel junctions were fabricated by a radio frequency magnetron sputtering at room temperature with hard mask on glass and $4^{\circ}$ tilt cut Si (111) substrates. The barrier layer was formed through two steps. After the Al layer was deposited, it was oxidized in the chamber of a reactive ion etching system (RIE) with $O_2$plasma at various conditions. The dependence of the TMR value and junction resistance on the thickness of Al layer (before oxidation) and oxidation parameters were investigated. Magnetoresistance value of 7% at room temperature was obtained by optimizing the Al layer thickness and oxidation conditions. Circular shape junctions on $4^{\circ}$tilt cut Si (111) substrate showed 4% magnetoresistance. Photovoltaic energy conversion effect was observed with the cross-strip geometry junctions on Si substrate.

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Fabrication of polycrystalline Si films by rapid thermal annealing of amorphous Si film using a poly-Si seed layer grown by vapor-induced crystallization

  • Yang, Yong-Ho;An, Gyeong-Min;Gang, Seung-Mo;An, Byeong-Tae
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2010.05a
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    • pp.58.1-58.1
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    • 2010
  • We have developed a novel crystallization process, where the crystallization temperature is lowered compared to the conventional RTA process and the metal contamination is lowered compared to the conventional VIC process. A very-thin a-Si film was deposited and crystallized at $550^{\circ}C$ for 3 h by the VIC process and then a thick a-Si film was deposited and crystallized by the RTA process at $680^{\circ}C$ for 5 min using the VIC poly-Si layer as a crystallization seed layer. The RTA crystallized temperature could be lowered up to $50^{\circ}C$, compared to RTA process alone. The poly-Si film appeared a needle-like growth front and relatively well-arranged (111) orientation. In addition, the Ni concentration in the poly-Si film was lowered to $3{\times}10^{17}\;cm^{-3}$ and that at the poly-Si/$SiO_2$ interface was lowered to $5{\times}10^{19}\;cm^{-3}$. The reduction in metal contamination could be greatly helpful to achieve a low leakage current in poly-Si TFT, which is the critical parameter for commercialization of AMOLED.

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