• Title/Summary/Keyword: Si membrane structure

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Fabrication and yield improvement of oxide semiconductor thin film gas sensor array (산화물 반도체 박막 가스센서 어레이의 제조 및 수율 개선)

  • 이규정;류광렬;허창우
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.2
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    • pp.315-322
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    • 2002
  • A thin film oxide semiconductor micro gas sensor array which shows only 60㎽ of power consumption at an operating temperature of 30$0^{\circ}C$ has been fabricated using microfabrication and rnicrornachining techniques. Excellent thermal insulation of the membrane is achieved by the use of a double la! or structure of 0.1${\mu}{\textrm}{m}$ thick Si$_3$N$_4$ and 1${\mu}{\textrm}{m}$ thick phosphosilicate glass(PSG) prepared by low pressure chemical vapor deposition(LPCVD) and atmospheric-pressure chemical-vapor deposition(APCVD), respectively. The sensor way consists of such thin film oxide semiconductor sensing materials as 1wt.% Pd-doped SnO$_2$, 6wt.% AI$_2$O$_3$-doped ZnO, WO$_3$ and ZnO. The thin film oxide semiconductor micro gas sensor array exhibited resistance changes usable for subsequent data processing upon exposure to various gases and the sensitivity strongly depended on the sensing layer materials. Heater Part of the sensor structure has been modified in order to improve the process yield of the sensor, and as a result of modified heater structure improved process yield has been achieved.

Electrical Properties of Alcohol Vapor Sensors Based on Porous Silicon

  • Park, Kwang-Youl;Kang, Kyung-Suk;Kim, Seong-Jeen;Lee, Sang-Hoon;Park, Bok-Gil;Sung, Man-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.12S
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    • pp.1232-1236
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    • 2003
  • In this work, we fabricated a gas-sensing device based on porous silicon(PS), and its C-V properties were investigated for sensing alcohol vapor. The structure of the sensor consists of thin Au/oxidized PS/PS/P-Si/Al, where the p-Si is etched anisotropically to be prepared into a membrane-shape. We used alcohol gases vaporized from different alcohol (or ethanol) solutions mixed with pure water at 36$^{\circ}C$, similarly with an alcohol breath measurement to check drunk driving. As the result, I-V curves showed typical tunneling property, and C-V curves were shaped like those of a MIS (metal-insulator-semiconductor) capacitor, where the capacitance in accumulation was increased with alcohol vapor concentration.

Transport Properties of CO2 and CH4 using Poly(ether-block-amide)/GPTMS Hybird Membranes (Poly(ether-block-amide)/GPTMS 하이브리드 분리막을 이용한 이산화탄소와 메탄의 투과특성)

  • Lee, Keun Chul;Kim, Hyunjoon
    • Korean Chemical Engineering Research
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    • v.54 no.5
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    • pp.653-658
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    • 2016
  • Poly(ether-block-amide)(PEBAX$_{(R)}$) resin is a thermoplastic elastomer combining linear chains of hard-rigid polyamide block interspaced soft-flexible polyether block. It was believed that the hard polyamide block provides the mechanical strength and permselectivity, whereas gas transport occurs primarily through the soft polyether block. The objective of this work was to investigate the gas permeation properties of carbon dioxide and methane for PEBAX$^{(R)}$-1657 membrane, and compare with those obtained for other grade of pure PEBAX$^{(R)}$, PEBAX$^{(R)}$-2533 and PEBAX$^{(R)}$ based hybrid membranes. The hybrid membranes based PEBAX$^{(R)}$ were obtained by a sol-gel process using GPTMS ((3-glycidoxypropyl) trimethoxysilane) as the only inorganic precursor. Molecular structure and morphology of membrane were analyzed by $^{29}Si$-NMR, DSC and SEM. PEBAX$_{(R)}$-2533 membrane exhibited higher gas permeability coefficients than PEBAX$^{(R)}$-1657 membrane. This was explained by the increase of chain mobility. In contrast, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$-1657 membrane was higher than PEBAX$^{(R)}$-2533 membrane. It was explained by the decrease of diffusion selectivity caused by increase of chain mobility. For PEBAX$^{(R)}$/GPTMS hybrid membrane, gas permeability coefficients were decreased with reaction time. Gas permeability coefficient of $CH_4$ was more significantly decreased than $CO_2$. It can be explained by the reduction of chain mobility caused by the sol-gel process, and strong affinity of PEO segment with $CO_2$. Comparing with pure PEBAX$^{(R)}$-1657 membrane, ideal separation factor of $CO_2/CH_4$ for PEBAX$^{(R)}$/GPTMS hybrid membrane has decreased to 4.5%, and gas permeability coefficient of $CO_2$ has increased 3.5 times.

Fabrication of Uncooled Pyroelectric Infrared Detector using Surface M Micromachining Technology (표면 마이크로 가공기술을 이용한 비냉각 초전형 적외선 검출소자 제작)

  • 장철영;고성용;이석헌;김동진;김진섭;이재신;이정희;한석룡;이용현
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.115-118
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    • 2000
  • Uncooled pyroelectric infrared detectors based on BST(B $a_{-x}$S $r_{x}$Ti $O_3$) thin films have been fabricated by RF magnetron sputtering and surface Micromachining technology. The detectors form BST thin film ferroelectric capacitors grown by RF magnetron sputtering on N/O/N(S $i_3$ $N_4$/ $SiO_2$/S $i_3$ $N_4$) membrane. The sputtered BST thin film exhibits highly c-axis oriented crystal structure that no poling treatment for sensing applications is required. This is an essential factor to increase the yield for realization of an infrared image sensor. surface-Micromachining technology is used to lower the thermal mass of the detector by giving maximum sensor efficiency Gold-black is evaporated on top of the sensing elements used the thermal evaporator. fabricated uncooled pyroelectric infrared detectors is highly output voltage at the low temperature(1$^{\circ}C$).).).

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Micro-Fabrication and Thermal Characteristics of a Thermal Mass Air Flow Sensor for Real-time Applications (고응답 열식 질량공기유량센서의 제작 및 열거동 특성)

  • Park, Byung-Kyu;Lee, Joon-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.7
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    • pp.542-548
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    • 2008
  • A thermal mass air flow sensor (MAFS), which consists of a micro-heater and thermo-resistive sensors on the silicon-nitride ($Si_3N_4$) thin membrane structure, is micro-fabricated by MEMS processes. Two thermo-resistive temperature sensors are located at $100{\mu}m$ upstream and downstream from the micro-heater respectively. The thermal characteristics are measured to find the best measurement indicator. The micro-heater is operated under constant power condition, and four flow indicators are investigated. The normalized temperature indicator shows good physical meaning and is easy to use in practice. It is found that the configurations and heating power of thermal-resistive elements are the dominant factors to determine the range of the flow measurement in the MAFS with higher sensitivity and accuracy.

A Study on the Blind Type of Waterproofing Layer of Wheel Tracking of Test Method and Valuation on Working of Live Load (이동하중이 작용하는 비노출 방수층의 윤하중 시험방법 및 평가에 관한 연구)

  • Eom Deok-Jun;Seon Yun-Suk;Kwon Si-Won;Oh Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.11a
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    • pp.1-5
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    • 2005
  • There are a lot of problem about waterproofing membrane coating for concrete deck of bridge and waterproofing sheets for concrete of deck of bridge because it couldn't confirm waterproofing's defeat after construction. These problems make a waterproofing material damage and concrete deck of bridge damage. So It needs a lot of money for repair work and reinforcement work. Therefor the structure slab of using waterproofing material protect invasion of water. Also, Concrete deck of bridge need a endurance permeability for the reduction repair payment. In this study, An experimental study on the quality standardization test method waterproofing layer on working of live load

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Morphology and crystallinity of silkworm cocoons with different rearing seasons

  • Lee, Hye Gyeoung;Nho, Si Kab;Um, In Chul
    • International Journal of Industrial Entomology and Biomaterials
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    • v.43 no.1
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    • pp.16-21
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    • 2021
  • The silkworm cocoon has recently attracted the attention of researchers because of its usefulness as a biomedical material (e.g., usage in the development of the membrane for guided bone regeneration and usage as a starting material for the fabrication of natural silk nonwoven fabric). The silkworm variety and strain have been reported as one of the important factors affecting the structure and properties of silk materials. This study examines the morphology and the molecular conformation of the silkworm cocoon at different cocoon measurement points, as well as the effect of the silkworm strain and rearing season on the morphology and crystallinity of the silkworm cocoon. The results show that the morphology of the outside of the cocoon does not differ depending on the cocoon measurement points, but that of the inside does. The silkworm cocoon crystallinity is not affected by the cocoon division. Interestingly, the crystallinity of the outside of the Jam101 cocoon differs depending on the rearing season, whereas it does not in other silkworm strains.

Nano imprinting lithography fabrication for photonic crystal waveguides (나노 임프린트 공정에 의한 광자결정 도파로 제조공정)

  • Jung Une-Teak;Kim Chang-Soek;Jeong Myung-Yung
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.498-501
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    • 2005
  • Photonic crystals, periodic structure with a high refractive index contrast modulation, have recently become very interesting platform for manipulation of light. The existence of a photonic bandgap, a frequency range in which propagation of light is prevented in all direction, makes photonic crystal very useful in application where spatial localization of light is required for waveguide, beam splitter, and cavity. But fabrication of 3 dimensional photonic crystal is still difficult process. a concept that has recently attracted a lot of attention is a planar photonic crystal based on a dielectric membrane, suspended in the air, and perforated with 2 dimensional lattice of hole. We show that the polymer slabs suspended in air with triangular lattice of air hole can exhibit the in-plane photonic bandgap for TE-like modes. The fabrication of Si master with pillar structure using hot embossing process was investigated for 2 dimensional low-index-contrast photonic crystal waveguide.

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Micromachined pH Sensor Using Open Well Structures (개방형 우물 구조를 이용한 마이크로머신형 pH 센서)

  • Kim, Heung-Rak;Kim, Young-Deog;Jeong, Woo-Cheol;Kim, Kwang-Il;Kim, Dong-Su
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.4
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    • pp.347-353
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    • 2002
  • A structure of a glass electrode-type pH sensor for measuring any concentration of $H^+$ in an aqueous solution was embodied with bulk micromachining technology. Two open well structures were formed, and a reference electrode was secured by the Ag/AgCl thin film in the sloped side of the etched structure. A sensitive membrane of an indicator electrode for generating a potential by an exchange reaction to $H^+$ was made with a glass containing Na 20% or more finely so that its thickness might be $100{\mu}m$ or so, and then it was bonded to one pyramidal structure. A liquid junction for a current path was formed by filling an agar in the anisotropically etched part of the Si wafer, which had a size of $50{\mu}m{\times}50{\mu}m$, and then bonded it to the other. After complete fabrication of each part, it was filled with a 2M KCl reference solution and encapsulated the sensor structure with a cold expoxy. The potential value of fabricated pH sensor was about 90mV/pH in the standard pH solutions.