• Title/Summary/Keyword: Post-annealing Pressure

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A Study on the Annealing Effect of SnO Nanostructures with High Surface Area (높은 표면적을 갖는 SnO 나노구조물의 열처리 효과에 관한 연구)

  • Kim, Jong-Il;Kim, Ki-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.536-542
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    • 2018
  • Tin dioxide, $SnO_2$, is a well-known n-type semiconductor that shows change in resistance in the presence of gas molecules, such as $H_2$, CO, and $CO_2$. Considerable research has been done on $SnO_2$ semiconductors for gas sensor applications due to their noble property. The nanomaterials exhibit a high surface to volume ratio, which means it has an advantage in the sensing of gas molecules. In this study, SnO nanoplatelets were grown densely on Si substrates using a thermal CVD process. The SnO nanostructures grown by the vapor transport method were post annealed to a $SnO_2$ phase by thermal CVD in an oxygen atmosphere at $830^{\circ}C$ and $1030^{\circ}C$. The pressure of the furnace chamber was maintained at 4.2 Torr. The crystallographic properties of the post-annealed SnO nanostructures were investigated by Raman spectroscopy and XRD. The change in morphology was confirmed by scanning electron microscopy. As a result, the SnO nanostructures were transformed to a $SnO_2$ phase by a post-annealing process.

The effects of annealing of the ATO films prepared by RF magnetron sputtering (RF 마그네트론 스퍼터를 이용한 ATO 박막의 열처리 효과)

  • Park, Sei-Yong;Lee, Sung-Uk;Park, Mi-Ju;Kim, Young-Ryeol;Hong, Byung-You
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.270-271
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    • 2008
  • Antimony (6 wt%) doped tin oxide (ATO) films to improve conductivity were deposited on 7059 coming glass by RF magnetron sputtering method for application to transparent electrodes. The ATO film was deposited at a working pressure of 5 mTorr and RF power of 175 W. We investigated the effects of the post-annealing temperature on structural, electrical and optical properties of the ATO films. The films were annealed at temperatures ranging from $300^{\circ}C$ to $600^{\circ}C$ in step of $100^{\circ}C$ using RTA equipment in vacuum ambient. X-ray diffraction (XRD) measurements showed the ATO films to be crystallized with a strong (101) preferred orientation as the annealing temperature increased. Electrical resistivity decreased significantly with annealing temperatures up to $600^{\circ}C$. ATO film annealed at temperature of $600^{\circ}C$ showed the lowest resistivity of $5.6\times10^{-3}\Omega$-cm. Optical transmittance increased significantly with annealing temperatures up to $600^{\circ}C$. The highest transmittance was 90.8 % in the visible range from 400 to 800 nm.

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δ-Ferrite Behavior of Butt Weld Zone in Clad Steel Plates Depended on Holding Time of PWHT (클래드강 맞대기 용접부의 후열처리 유지시간에 따른 델타 페라이트 거동)

  • Park, Jae-Won;Lee, Chul-Ku
    • Journal of Welding and Joining
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    • v.32 no.2
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    • pp.29-36
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    • 2014
  • Recently, in order to enhance the function and usefulness of products, cladding of dissimilar materials that maximizes the performance of the material is being widely used in all areas of industry as an important process. Clad steel plate, produced by cladding stainless steel plate, an anticorrosive material, on carbon steel plate, is being used to produce pressure vessels. Stainless steel plate has good corrosion resistance, and carbon steel plate has good rigidity and strength; clad steel can satisfy all of these qualities at once. This study aims to find the ${\delta}$-ferrite behavior, mechanical properties, structure change, integrity and reliability of clad steel weld on hot rolled steel plates. For this purpose, multi-layer welding, repair welding and post weld heat treatment were implemented according to welding procedure specifications (WPS). In order to observe the mechanical properties and toughness of clad steel weld zone, post weld heat treatment was carried out according to ASME Sec. VIII Div.1 UW-40 procedure for post weld heat treatment. With heat treatment at $625^{\circ}C$, the hold time was used as the process variable, increased by intervals that were doubled each time, from 80 to 1,280 min. The structure of weld part was typical cast structure; localized primary austenite areas appeared near central vermicular ferrite and fusion line. The heat affected zone showed rough austenite structure created by the weld heat input. Due to annealing effects of heat treatment, the mechanical properties (tensile strength, hardness, impact value) of the heat affected area tended to decrease. From the results of this study, it is possible to conclude the integrity of clad steel welds is not affected much in field welding, repair welding, multi-layer welding, post weld heat treatment, etc.

Low-temperature crystallization of high-dielectric (Ba,Sr)$TiO_3$ thin films for embedded capacitors

  • Cho, Kwang-Hwan;Kang, Min-Gyu;Kang, Chong-Yun;Yoon, Seok-Jin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.03a
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    • pp.21-21
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    • 2010
  • (Ba,Sr)$TiO_3$ (BST) thin film with a perovskite structure has potential for the practical application in various functional devices such as nonvolatile-memory components, capacitor, gate insulator of thin-film transistors, and electro-optic devices for display. Normally, the BST thin films derived from sol-gel and sputtering are amorphous or partially crystalline when processed below $600^{\circ}C$. For the purpose of integrating BST thin film directly into a Si-based read-out integrated circuit (ROIC), it is necessary to process the BST film below $400^{\circ}C$. The microstructural and electrical properties of low-temperature crystallized BST film were studied. The BST thin films have been fabricated at $350^{\circ}C$ by UV-assisted rapidly thermal annealing (RTA). The BST films are in a single perovskite phase and have well-defined electrical properties such as high dielectric constant, low dielectric loss, low leakage current density, and high breakdown voltage. Photoexcitation of the organics contained in the sol-gel-derived films by high-intensity UV irradiation facilitates elimination of the organics and formation of the single-crystalline phase films at low temperatures. The amorphous BST thin film was transformed to a highly (h00)-oriented perovskite structure by high oxygen pressure processing (HOPP) at as low as $350^{\circ}C$. The dielectric properties of BST film were comparable to (or even better than) those of the conventionally processed BST films prepared by sputtering or post-annealing at temperature above $600^{\circ}C$. When external pressure was applied to the well-known contractive BST system during annealing, the nucleation energy barrier was reduced; correspondingly, the crystallization temperature decreased. The UV-assisted RTA and HOPP, as compatible with existing MOS technology, let the BST films be integrated into radio-frequency circuit and mixed-signal integrated circuit below the critical temperature of $400^{\circ}C$.

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RBS Analysis on the Si0.9Ge0.1 Epitaxial Layer for the fabrication of SiGe HBT (SiGe HBT 제작을 위한 실리콘 게르마늄 단결정 박막의 RBS 분석)

  • 한태현;안호명;서광열
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.9
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    • pp.916-923
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    • 2004
  • In this paper, the strained Si$_{0.9}$Ge$_{0.1}$ epitaxial layers grown by a reduced pressure chemical vapor deposition (RPCVD) on Si (100) were characterized by Rutherford backscattering spectrometery (RBS) for the fabrication of an SiGe heterojunction bipolar transistor(HBT). RBS spectra of the ${Si}_0.9{Ge}_0.1$epitaxial layers grown on the Si substrates which were implanted with the phosphorus (P) ion and annealed at a temperature between $850^{\circ}C$ - $1000^{\circ}C$ for 30min were analyzed to investigate the post thermal annealing effect on the grown${Si}_0.9{Ge}_0.1$epitaxial layer quality. Although a damage of the substrates by P ion-implantation might be cause of the increase of RBS yield ratios, but any defects such as dislocation or stacking fault in the grown ${Si}_0.9{Ge}_0.1$ epitaxial layer were not found in transmission electron microscope (TEM) photographs. The post high temperature rapid thermal annealing (RTA) effects on the crystalline quality of the ${Si}_0.9{Ge}_0.1$ epitaxial layers were also analyzed by RBS. The changes in the RBS yield ratios were negligible for RTA a temperature between $900^{\circ}C$ - $1000^{\circ}C$for 20 sec, or $950^{\circ}C$for 20 sec - 60 sec. A SiGe HBT array shows a good Gummel characteristics with post RTA at $950^{\circ}C$ for 20 sec.sec.sec.

P-type Electrical Characteristics of the Amorphous La2NiO4+δ Thin Films

  • Hop, Dang-Hoang;Lee, Jung-A;Heo, Young-Woo;Kim, Jeong-Joo;Lee, Joon-Hyung
    • Journal of the Korean institute of surface engineering
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    • v.51 no.4
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    • pp.231-236
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    • 2018
  • We report p-type electrical characteristics of the amorphous $La_2NiO_{4+{\delta}}$ thin films which were sputtered on the glass substrates using an RF sputtering system. As-deposited thin films at room temperature and $300^{\circ}C$ were amorphous in nature. Post-annealing of the thin film samples over $400^{\circ}C$ resulted in the nano-crystallization of the $La_2NiO_{4+{\delta}}$. The electrical properties of the films were much dependent on the oxygen partial pressure, temperature of the post-annealing and sputtering ambient. The as-deposited samples at room temperature show a hole concentration of $7.82{\times}10^{13}cm^{-3}$, and it could be increased as high as $3.51{\times}10^{22}cm^{-3}$ when the films were post-annealed in an oxygen atmosphere at $500^{\circ}C$. Such p-type conductivity behavior of the $La_2NiO_{4+{\delta}}$ films suggests that the amorphous and nano-crystallized $La_2NiO_{4+{\delta}}$ films have potential for the application as p-type semiconductive or conductive materials at low temperatures where material diffusion is limited.

Fabrication and Characterizations of ITO Film as a Transparent Conducting Electrode for PDP Application (PDP 투명전극의 응용을 위한 ITO 박막의 제작평가)

  • Park, Kang-Il;Lim, Dong-Gun;Kwak, Dong-Joo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.788-791
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    • 2002
  • Tin doped indium oxide(ITO) films are highly conductive and transparent in the visible region whose property leads to the applications in solar cell, liquid crystal display, thermal heater, and other sensors. This paper investigated ITO films as a transparent conducting films for application of PDP. ITO films were grown on glass substrate by RF magnetron sputtering method. To achieve high transmittance and low resistivity, we examined the various film deposition such as substrate temperature, gas pressure, annealing temperature, and deposition time. We recommend the substrate temperature of $500^{\circ}C$ and post annealing of $200^{\circ}C$ in $O_2$ atmosphere for good conductivity and transmittance. From XRD examination, ITO films showed a preferred(222) orientation. As substrate temperature increased from RT to $500^{\circ}C$, the intensity of the (222) peak increased. The highest peak intensity was observed at a substrate temperature of $500^{\circ}C$. with the optimum growth conditions, ITO films showed resistivity of $1.04{\times}10^{-4}{\Omega}-cm$ and transmittance of 81.2% for a film 300nm thick in the wavelength range of the visible spectrum.

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Synthesis of Mixed Phase Vanadium Oxides Thin Films and Their Ethanol Gas Sensing Properties (혼합 상의 바나듐 산화물 박막 제작 및 에탄올 가스 감지 특성 연구)

  • Han, Soo Deok;Kang, Chong-Yun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.1
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    • pp.29-33
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    • 2018
  • Using a vanadium dioxide ($VO_2$) source, highly pure and amorphous vanadium oxide (VO) thin films were deposited using an e-beam evaporator at room temperature and high vacuum (<$10^{-7}$ Torr). Then, by controlling the post-annealing conditions such as $N_2:O_2$ pressure ratio and annealing time, we could easily synthesize a homogeneous $VO_2$ thin film and also mixed-phase VO thin films, including $VO_2$, $V_2O_5$, $V_3O_7$, $V_5O_9$, and $V_6O_{13}$. The crystallinity and phase of these were characterized by X-ray diffraction, and the surface morphology by FE-SEM. Moreover, the electrical properties and ethanol sensing measurements of the VO thin films were analyzed as a function of temperature. In general, mixed-phases as a self-doping effect have enhanced electrical properties, with a high carrier density and an enhanced response to ethanol. In summary, we developed an easy, scalable, and reproducible fabrication process for VO thin films that is a promising candidate for many potential electrical and optical applications.

Dependence of RF power of ($Ba_{0.5}Sr_{0.5})TiO_3$ thin film using RF magnetron sputtering (RF magnetron sputtering을 이용한 ($Ba_{0.5}Sr_{0.5})TiO_3$ 박막의 RF power 의 존성)

  • 최형윤;이태일;정순원;박인철;최동한;김흥배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.51-54
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    • 2000
  • In this paper, $Ba_{0.5}$Sr$_{0.5}$TiO$_3$ thin films were prepared on Pt/Ti/SiO$_2$/Si substrate by RF magnetron sputtering method. We investigated effect of deposition conditions (especially RF input power) on structural properties of BST thin films. Deposit conditions of BST films were set working gas ratio, Ar:O$_2$= 70 : 30, working pressure 10mTorr, and RF input power 25W, 50W, 75W and 100W. Post-annealing using rapid thermal annealing(RTA) performed at 45$0^{\circ}C$, 55$0^{\circ}C$, $650^{\circ}C$, and 75$0^{\circ}C$ in oxigen ambient for 60 sec, respectively. The structural properties of BST films on Pt/Ti/SiO$_2$/Si substrate analysed by X-ray diffraction(XRD).).).

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Optimization of Electrical and Optical Properties of a-IZO Thin Film for High-Efficiency Solar Cells (고효율 태양전지용 a-IZO 박막의 전기적 및 광학적 특성 최적화에 관한 연구 )

  • Somin Park;Sungjin Jeong;Jiwon Choi;Youngkuk Kim;Junsin Yi
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.1
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    • pp.49-55
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    • 2023
  • The deposition of indium zinc oxide (IZO) thin films was carried out on substrate at room temperature by RF magnetron sputtering. The effects of substrate temperature, RF power and deposition pressure were investigated with respect to physical and optical properties of films such as deposition rate, electrical properties, structure, and transmittance. As the RF power increases, the resistivity gradually decreases, and the transmittance slightly decreases. For the variation of deposition pressure, the resistivity greatly increases, and the transmittance is decreased with increasing deposition pressure. As a result, it was demonstrated that an IZO film with the resistivity of 3.89 × 10-4 Ω∙cm, the hole mobility of 51.28 cm2/Vs, and the light transmittance of 86.89% in the visible spectrum at room temperature can be prepared without post-deposition annealing.