• Title/Summary/Keyword: silicon fabrication

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Fabrication of Macroporous Silicon Diaphragms (매크로기공을 갖는 다공질 실리콘 다이어프램의 제작)

  • Min, Nam-Ki;Ha, Dong-Sik;Jeong, Woo-Sik;Min, Suk-Ki
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1558-1560
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    • 1998
  • Macroporous silicon diaphragms 20 to $200{\mu}m$ thick have been formed on p-type silicon by anistropic etching in TMAH solution and then by electrochemical etching in HF-ethanol-water solution with an applied current. The pores have a pore diameter of $1.5{\sim}2{\mu}m$, with a depth of $20{\sim}30{\mu}m$ and are not interconnected, which are in sharp contrast to the porous silicon reported previouly for similarly doped p-Si. The fabrication of macroporous silicon and free-standing diaphragms is expected to offer new applications for microsensors, micro-machining, and separators.

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Fabrication and Characterization of Solar Cells Using Cast Polycrystalline Silicon (Cast Poly-Si을 이용한 태양전지 제작 및 특성)

  • 구경완;소원욱;문상진;김희영;홍봉식
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.2
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    • pp.55-62
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    • 1992
  • Polycrystalline silicon ingots were manufactured using the casting method for polycrystalline silicon solar cells. These ingots were cut into wafers and ten n$^{+}$p type solar cells were made through the following simple process` surface etching, n$^{+}$p junction formation, metalization and annealing. For the grain boundary passivation, the samples were oxidized in O$_2$ for 5 min. at 80$0^{\circ}C$ prior to diffusion in Ar for 100 min. at 95$0^{\circ}C$. The conversion efficiency of polycrystalline silicon solar cells made from these wafers showed about 70-80% of those of the single crystalline silicon solar cell and superior conversion efficiency, compared to those of commercial polycrystalline wafers of Wacker Chemie. The maximum conversion efficiency of our wafers was indicated about 8%(without AR coating) in spite of such a simple fabrication method.

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Buried contact solar cells using tri-crystalline silicon wafer (삼상 실리콘 기판을 사용한 저가 전극 함몰형 태양전지)

  • Kwon, Jea-Hong;Lee, Soo-Hong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.176-180
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    • 2003
  • Tri-crystalline silicon (Tri-Si) wafers have three different orientations and three grain boundaries. In this paper, tri-Si wafers have been used for the fabrication of buried contact solar cells. The optical and micro-structural properties of these cells after texturing in KOH solution have been investigated and compared with those of cast multi-crystalline silicon (multi-Si) wafers. We employed a cost effective fabrication process and achieved buried contact solar cell (BCSC) energy conversion efficiencies up to 15% whereas the cast multi-Si wafer has efficiency around 14%.

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A Study on Silicon Nitride Based Ceramic Cutting Tool Materials

  • Park, Dong-Soo
    • Tribology and Lubricants
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    • v.11 no.5
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    • pp.78-86
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    • 1995
  • The silicon nitride based ceramic cutting tool materials have been fabricated by gas pressure sintering (GPS) or hot pressing (HP). Their mechanical properties were measured and the effect of the fabrication variables on the properties were examined. Also, effect of adding TiN or TiC particulates on the mechanical properties of the silicon nitride ceramics were investigated. Ceramic cutting tools (ISO 120408) were made of the sintered bodies. Cutting performance test were performed on either conventional or NC lathe. The workpieces were grey cast iron, hardened alloy steel (AISI 4140, HRc>60) and Ni-based superalloy (Inconel 718). The results showed that fabrication variables, namely, sintering temperature and time, exerted a strong influence on the microstincture and mechanical properties of the sintered body, which, however, did not make much difference in wear resistance of the tools. High hardness of the tool containing TiC particulates exhibited good cutting performance. Extensive crater wear was observed on both monolithic and TiN-containing silicon nitride tools after cutting the hardened alloy steel. Inconel 718 was extremely difficult to cut by the current cutting tools.

Fabrication and Mechanical Properties of Porous Silicon Carbide Ceramics from Silicon and Carbon Mixture (실리콘과 카본을 이용한 다공질 탄화규소의 제조와 기계적 특성)

  • Kim, Jong-Chan;Lee, Eun Ju;Kim, Deug-Joong
    • Journal of the Korean Ceramic Society
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    • v.50 no.6
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    • pp.429-433
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    • 2013
  • Silicon, carbon, and B4C powders were used as raw materials for the fabrication of porous SiC. ${\beta}$-SiC was synthesized at $1500^{\circ}C$ in an Ar atmosphere from a silicon and carbon mixture. The synthesized powders were pressed into disk shapes and then heated at $2100^{\circ}C$. ${\beta}$-SiC particles transformed to ${\alpha}$-SiC at over $1900^{\circ}C$, and rapid grain growth of ${\alpha}$-SiC subsequently occurred and a porous structure with elongated plate-type grains was formed. The mechanism of this rapid grain growth is thought to be an evaporation-condensation reaction. The mechanical properties of the fabricated porous SiC were investigated and discussed.

Wafer-level Fabrication of Ball Lens by Cross-cut and Reflow of Wafer-bonded Glass on Silicon

  • Lee, Dong-Whan;Oh, Jin-Kyung;Choi, Jun-Seok;Lee, Hyung-Jong;Chung, Woo-Nam
    • Journal of the Optical Society of Korea
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    • v.14 no.2
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    • pp.163-169
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    • 2010
  • Novel wafer-level fabrication of a glass ball-lens is realized for optoelectronic applications. A Pyrex wafer is bonded to a silicon wafer and cross-cut into a square-tile pattern, followed by wet-etching of the underlying silicon. Cubes of Pyrex on the undercut silicon are then turned into ball shapes by thermal reflow, and separated from the wafer by further etching of the silicon support. Radial variation and surface roughness are measured to be less than ${\pm}3\;{\mu}m$ and ${\pm}1\;nm$, respectively, for ball diameter of about $500\;{\mu}m$. A surface defect on the ball that is due to the silicon support is shown to be healed by using a silicon-optical-bench. Optical power-relay of the ball lens showed the maximum efficiency of 65% between two single-mode fibers on the silicon-optical-bench.

Nanostencil fabrication using FIB milling (FIB 밀링을 이용한 나노스텐실 제작)

  • 김규만;정성일;오현석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.871-874
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    • 2004
  • Fabrication of a high-resolution shadow mask, or called nanostencil, is presented. This high-resolution shadowmask is fabricated by a combination of MEMS processes and focused ion beam (FIB) milling. 500 nm thick and 2x2 mm large membranes are made on a silicon wafer by micro-fabrication processes of LPCVD, photolithography, ICP etching and bulk silicon etching. Subsequent FIB milling enabled local membrane thinning and aperture making into the thinned silicon nitride membrane. Due to high resolution of FIB milling process, nanoscale apertures down to 70 nm could be made into the membrane.

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The fabrication of micro mass flow sensor by Micro-machining Technology (Micromachining 기술을 이용한 micro mass flow sensor의 제작)

  • Eoh, Soo-Hae;Choi, Se-Gon
    • Proceedings of the KIEE Conference
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    • 1987.07a
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    • pp.481-485
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    • 1987
  • The fabrication of a micro mass flow sensor on a silicon chip by means of micro-machining technology is described on this paper. The operation of micro mass flow sensor is based on the heat transfer from a heated chip to a fluid. The temperature differences on the chip is a measure for the flow velocity in a plane parallel with the chip surface. An anisotropic etching technigue was used for the formation of the V-type groove in this fabrication. The micro mass flow sensor is made up of two main parts ; A thin glass plate embodying the connecting parts and mass flow sensor parts in silicon chip. This sensor have a very small size and a neglible dead space. Micro mass flow sensor can fabricate on silicon chip by micro machining technology too.

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Silicon wire array fabrication for energy device (실리콘 와이어 어레이 및 에너지 소자 응용)

  • Kim, Jae-Hyun;Baek, Seung-Ho;Kim, Kang-Pil;Woo, Sung-Ho;Lyu, Hong-Kun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.440-440
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    • 2009
  • Semiconductor nanowires offer exciting possibilities as components of solar cells and have already found applications as active elements in organic, dye-sensitized, quantum-dot sensitized, liquid-junction, and inorganic solid-state devices. Among many semiconductors, silicon is by far the dominant material used for worldwide photovoltaic energy conversion and solar cell manufacture. For silicon wire to be used for solar device, well aligned wire arrays need to be fabricated vertically or horizontally. Macroscopic silicon wire arrays suitable for photovoltaic applications have been commonly grown by the vapor-liquid-solid (VLS) process using metal catalysts such as Au, Ni, Pt, Cu. In the case, the impurity issues inside wire originated from metal catalyst are inevitable, leading to lowering the efficiency of solar cell. To escape from the problem, the wires of purity of wafer are the best for high efficiency of photovoltaic device. The fabrication of wire arrays by the electrochemical etching of silicon wafer with photolithography can solve the contamination of metal catalyst. In this presentation, we introduce silicon wire arrays by electrochemical etching method and then fabrication methods of radial p-n junction wire array solar cell and the various merits compared with conventional silicon solar cells.

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The Characteristics of Focused Ion Beam Utilized Silicon Mold Fabrication on the Micro/Nano Scale (집속이온빔을 이용한 마이크로/나노스케일에서의 실리콘 금형 가공 특성)

  • Kim, Heung-Bae;Noh, Sang-Lai
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.8
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    • pp.966-974
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    • 2011
  • The use of ion beams in the micro/nano scale is greatly increased by technology development. Especially, focused ion beams (FIBs) have a great potential to fabricate the device in sub micro scale. Nevertheless, FIB has several limitations, surface swelling in low ion dose regime, precipitation of incident ions, and the redeposition effect due to the sputtered atoms. In this research, we demonstrate a way which can be used to fabricate mold structures on a silicon substrate using FIBs. For the purpose of the demonstration, two essential subjects are necessary. One is that focused ion beam diameter as well as shape has to be measured and verified. The other one is that the accurate rotational symmetric model of ion-solid interaction has to be mathematically developed. We apply those two, measured beam diameter and mathematical model, to fabricate optical lenses mold on silicon. The characteristics of silicon mold fabrication will be discussed as well as simulation results.